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Definitions for Simplicial principal bundles in parametrized spaces

Definition
QAlgorithms_Papers_Independent_Intakethird100_P73

by Gohan · Nov 1, 2026 · Mathlib 0df444a (Lean v4.33.1)

prove2quantum

The objects the formalized statements of Simplicial principal bundles in parametrized spaces (arXiv:1203.2460) are stated in. Each was checked against the paper by a blind read-back and a moderator.

  • KSpace: A k-space, without a separation axiom (PDF p. 2).
  • kify: Kification, using the final topology for all compact Hausdorff probes (PDF p. 4, all products and limits are in K).
  • kifyProjection: The identity map from the kification to the original space.
  • kifyProbe: A compact Hausdorff probe is continuous into the kification by its definition.
  • kifyMap: Kification of a continuous map; neither topology is silently discarded.
  • IsWeaklyHausdorff: Weak Hausdorffness means that every compact Hausdorff probe has closed image (PDF p. 2). This does not require Hausdorffness.
  • SpaceOver: An object of K/B (PDF p. 2).
  • MapOver: A continuous map over the fixed base (PDF p. 2).
  • identityOver: Identity morphism over B.
  • composeOver: Composition of morphisms over B, in functional order.
  • FiberProductSet: The underlying set of a fiber product, with its ordinary subspace topology only as the input to kification. It is not used as the categorical product.
  • fiberProductOver: The actual fiber product over B with k-space topology (PDF pp. 4--5).
  • fiberProductSetMap: The map of underlying pullback subspaces induced by two maps over B.
  • fiberProductMap: Product of two given maps, with both pullback topologies kified. This is the product map, not the pushout-product (PDF p. 20).
  • FiberwiseHomotopic: Fiberwise homotopy: a continuous homotopy on the kified tensor X times I, with both endpoints specified and the projection fixed for every time (PDF pp. 4--5).
  • IsFEquivalence: An f-equivalence has an inverse over B and two fiberwise homotopies, not merely homotopy equivalences on separate fibers (PDF p. 5).
  • IsFFibration: The fiberwise covering homotopy property, for every test object in K/B (PDF p. 5). The entire lift is over B.
  • IsStrongFCofibration: Strong fbar-cofibrations have the LLP against all f-acyclic f-fibrations in K/B. Neither f-cofibrations nor NDR representations are substituted for this definition (PDF p. 5).
  • fiberPair: A point of the kified fiber product, retaining the common-base equation.
  • ParametrizedGroup: A group object in K/B, with continuous unit, multiplication, and inverse and all group axioms on each common fiber (PDF pp. 2, 5--6).
  • EquivariantSpace: A continuous right action over B; its domain is a kified fiber product, not the Cartesian product of possibly different fibers (PDF p. 6).
  • EquivariantMap: A G-equivariant map over B (PDF p. 6).
  • equivariantIdentity: Identity G-map.
  • equivariantCompose: Composite G-map in functional order.
  • EquivariantCylinderMap: A G-map X tensor I to Y. Equivariance is required at every time, with G acting trivially on I, and the homotopy stays over B (PDF pp. 6--7).
  • EquivariantlyHomotopic: Homotopy through G-maps over B with the specified endpoints (PDF p. 7).
  • IsEquivariantFEquivalence: An equivariant f-equivalence includes an equivariant inverse and both homotopies over B (PDF p. 7).
  • IsEquivariantFFibration: The equivariant covering homotopy property for every G-space over B (PDF p. 7).
  • IsEquivariantStrongFCofibration: The LLP in G K/B against all equivariant f-acyclic f-fibrations (PDF p. 7). This is stronger than a condition only on underlying maps.
  • IsEquivariantFiberwiseNDR: The source's right-equivariant fiberwise NDR condition (PDF pp. 5, 7). The zero set is exactly A, A is fixed for all times, and only u(x) < 1 requires the terminal homotopy value to lie in A.
  • GroupMapOver: A continuous homomorphism of parametrized groups (PDF pp. 2, 8). Preservation of inverses follows from these group homomorphism axioms.
  • SimplicialParametrizedGroup: A simplicial parametrized group is contravariant functor data on the whole simplex category, taking every arrow to a continuous homomorphism. The identity and composition equations specify the full simplicial object; levels are not arbitrary unrelated groups (PDF p. 2).
  • constantSimplicialGroup: The constant simplicial parametrized group, for a sanity check.
  • baseOver: The terminal object B→B, which is the domain of the identity section.
  • groupUnitSection: The canonical identity section as a map over B (PDF pp. 5--6).
  • IsWellSectioned: Well-sectionedness is the strong cofibration property of the canonical identity section, not an arbitrary supplied section (Definition 6, PDF p. 6).
  • IsGoodSimplicialGroup: Goodness requires every degeneracy in every degree to be a strong fbar-cofibration (Definition 20, PDF p. 12).
Definition code
import Mathlib

/-!
Local definitions for Roberts--Stevenson, arXiv:1203.2460v4, PDF pp. 2, 4--5, 20.
Products below have the compactly generated topology. No weak Hausdorff
condition is imposed on total spaces. The other planned nodes are explicitly
deferred in this paper's HARD.md and GAPS.json, rather than weakened.
-/

noncomputable section

universe u

namespace QAlgorithms.Papers.Independent.Intakethird100.P73

open CategoryTheory

open scoped Topology

/-- A k-space, without a separation axiom (PDF p. 2). -/
structure KSpace where
  Carrier : Type u
  topology : TopologicalSpace Carrier
  generated : @CompactlyGeneratedSpace Carrier topology

/-- Use the carrier of the bundled k-space, without changing its topology. -/
instance kSpaceCoeSort : CoeSort KSpace.{u} (Type u) := ⟨KSpace.Carrier⟩

/-- Recover exactly the topology stored in the bundled k-space. -/
instance kSpaceTopology (X : KSpace.{u}) : TopologicalSpace X := X.topology

/-- Recover the compact-generation witness for that same stored topology. -/
instance kSpaceCompactlyGenerated (X : KSpace.{u}) : CompactlyGeneratedSpace X := X.generated

/-- Kification, using the final topology for all compact Hausdorff probes
(PDF p. 4, all products and limits are in K). -/
def kify (X : Type u) [TopologicalSpace X] : KSpace where
  Carrier := X
  topology := TopologicalSpace.compactlyGenerated.{u} X
  generated := by
    let T := Σ i : (S : CompHaus.{u}) × C(S, X), i.fst
    let q : T → X := fun z => z.1.2 z.2
    letI : TopologicalSpace X := TopologicalSpace.compactlyGenerated.{u} X
    exact uCompactlyGeneratedSpace_of_coinduced (f := q) continuous_coinduced_rng rfl

/-- The identity map from the kification to the original space. -/
def kifyProjection (X : Type u) [tX : TopologicalSpace X] : C(kify X, X) where
  toFun := id
  continuous_toFun := by
    change Continuous[TopologicalSpace.compactlyGenerated.{u} X, tX] (id : X → X)
    exact @continuous_from_compactlyGenerated.{u, u, u} X X tX tX id
      (fun _ g => g.continuous)

/-- A compact Hausdorff probe is continuous into the kification by its definition. -/
def kifyProbe {X : Type u} [TopologicalSpace X] (S : CompHaus.{u})
    (f : C(S, X)) : C(S, kify X) where
  toFun := f
  continuous_toFun := by
    change Continuous[inferInstance, TopologicalSpace.coinduced
      (fun z : (Σ i : (T : CompHaus.{u}) × C(T, X), i.fst) => z.1.2 z.2)
      inferInstance] (f : S → X)
    let T := Σ i : (U : CompHaus.{u}) × C(U, X), i.fst
    let q : T → X := fun z => z.1.2 z.2
    let j : S → T := fun s => ⟨⟨S, f⟩, s⟩
    have hj : Continuous j := continuous_sigmaMk
      (σ := fun i : (U : CompHaus.{u}) × C(U, X) => (i.fst : Type u))
      (i := (⟨S, f⟩ : (U : CompHaus.{u}) × C(U, X)))
    exact @Continuous.comp S T X inferInstance inferInstance
      (TopologicalSpace.coinduced q inferInstance) j q
      (continuous_coinduced_rng (f := q) (t := inferInstance)) hj

/-- Kification of a continuous map; neither topology is silently discarded. -/
def kifyMap {X Y : Type u} [tX : TopologicalSpace X] [tY : TopologicalSpace Y]
    (f : C(X, Y)) : C(kify X, kify Y) where
  toFun := f
  continuous_toFun := by
    change Continuous[TopologicalSpace.compactlyGenerated.{u} X,
      TopologicalSpace.compactlyGenerated.{u} Y] (f : X → Y)
    exact @continuous_from_compactlyGenerated.{u, u, u} X Y tX
      (TopologicalSpace.compactlyGenerated.{u} Y) (f : X → Y)
      (fun S g => (kifyProbe S (f.comp g)).continuous)

/-- Weak Hausdorffness means that every compact Hausdorff probe has closed image
(PDF p. 2). This does not require Hausdorffness. -/
def IsWeaklyHausdorff (B : KSpace.{u}) : Prop :=
  ∀ (S : CompHaus.{u}) (f : C(S, B)), IsClosed (Set.range f)

/-- An object of K/B (PDF p. 2). -/
structure SpaceOver (B : KSpace.{u}) where
  space : KSpace.{u}
  projection : C(space, B)

/-- A continuous map over the fixed base (PDF p. 2). -/
structure MapOver {B : KSpace} (X Y : SpaceOver B) where
  map : C(X.space, Y.space)
  over_base : ∀ x, Y.projection (map x) = X.projection x

/-- Identity morphism over B. -/
def identityOver {B : KSpace} (X : SpaceOver B) : MapOver X X where
  map := ContinuousMap.id X.space
  over_base := fun _ => rfl

/-- Composition of morphisms over B, in functional order. -/
def composeOver {B : KSpace} {X Y Z : SpaceOver B}
    (g : MapOver Y Z) (f : MapOver X Y) : MapOver X Z where
  map := g.map.comp f.map
  over_base := fun x => (g.over_base (f.map x)).trans (f.over_base x)

/-- The underlying set of a fiber product, with its ordinary subspace topology
only as the input to kification. It is not used as the categorical product. -/
abbrev FiberProductSet {B : KSpace} (X Y : SpaceOver B) :=
  {z : X.space × Y.space // X.projection z.1 = Y.projection z.2}

/-- The actual fiber product over B with k-space topology (PDF pp. 4--5). -/
def fiberProductOver {B : KSpace} (X Y : SpaceOver B) : SpaceOver B where
  space := kify (FiberProductSet X Y)
  projection :=
    (⟨fun z : FiberProductSet X Y => X.projection z.val.1, by fun_prop⟩ :
      C(FiberProductSet X Y, B)).comp (kifyProjection (FiberProductSet X Y))

/-- The map of underlying pullback subspaces induced by two maps over B. -/
def fiberProductSetMap {B : KSpace} {A X D Y : SpaceOver B}
    (f : MapOver A X) (g : MapOver D Y) :
    C(FiberProductSet A D, FiberProductSet X Y) where
  toFun := fun z => ⟨(f.map z.val.1, g.map z.val.2),
    (f.over_base z.val.1).trans (z.property.trans (g.over_base z.val.2).symm)⟩
  continuous_toFun := by fun_prop

/-- Product of two given maps, with both pullback topologies kified.
This is the product map, not the pushout-product (PDF p. 20). -/
def fiberProductMap {B : KSpace} {A X D Y : SpaceOver B}
    (f : MapOver A X) (g : MapOver D Y) :
    MapOver (fiberProductOver A D) (fiberProductOver X Y) where
  map := kifyMap (fiberProductSetMap f g)
  over_base := fun z => f.over_base z.val.1

/-- Fiberwise homotopy: a continuous homotopy on the kified tensor X times I,
with both endpoints specified and the projection fixed for every time
(PDF pp. 4--5). -/
def FiberwiseHomotopic {B : KSpace} {X Y : SpaceOver B}
    (f g : MapOver X Y) : Prop :=
  ∃ H : C(kify (X.space × unitInterval), Y.space),
    (∀ x, H (x, 0) = f.map x) ∧
    (∀ x, H (x, 1) = g.map x) ∧
    ∀ x t, Y.projection (H (x, t)) = X.projection x

/-- An f-equivalence has an inverse over B and two fiberwise homotopies,
not merely homotopy equivalences on separate fibers (PDF p. 5). -/
def IsFEquivalence {B : KSpace} {X Y : SpaceOver B} (f : MapOver X Y) : Prop :=
  ∃ g : MapOver Y X,
    FiberwiseHomotopic (composeOver g f) (identityOver X) ∧
    FiberwiseHomotopic (composeOver f g) (identityOver Y)

/-- The fiberwise covering homotopy property, for every test object in K/B
(PDF p. 5). The entire lift is over B. -/
def IsFFibration {B : KSpace} {X Y : SpaceOver B} (p : MapOver X Y) : Prop :=
  ∀ (Z : SpaceOver B) (a : MapOver Z X)
    (H : C(kify (Z.space × unitInterval), Y.space)),
    (∀ z t, Y.projection (H (z, t)) = Z.projection z) →
    (∀ z, H (z, 0) = p.map (a.map z)) →
    ∃ L : C(kify (Z.space × unitInterval), X.space),
      (∀ z t, X.projection (L (z, t)) = Z.projection z) ∧
      (∀ z, L (z, 0) = a.map z) ∧
      ∀ z t, p.map (L (z, t)) = H (z, t)

/-- Strong fbar-cofibrations have the LLP against all f-acyclic f-fibrations
in K/B. Neither f-cofibrations nor NDR representations are substituted for
this definition (PDF p. 5). -/
def IsStrongFCofibration {B : KSpace} {A X : SpaceOver B} (i : MapOver A X) : Prop :=
  ∀ (U V : SpaceOver B) (p : MapOver U V),
    IsFFibration p → IsFEquivalence p →
    ∀ (a : MapOver A U) (b : MapOver X V),
      (∀ z, p.map (a.map z) = b.map (i.map z)) →
      ∃ l : MapOver X U,
        (∀ z, l.map (i.map z) = a.map z) ∧
        ∀ x, p.map (l.map x) = b.map x

/-- Sanity: identity maps have the stated lifting property. -/
example {B : KSpace} (X : SpaceOver B) :
    IsStrongFCofibration (identityOver X) := by
  intro U V p hp he a b h
  exact ⟨a, fun _ => rfl, h⟩

/-- Sanity: the product map acts on both coordinates, with no union or
pushout-product hidden in its definition. -/
example {B : KSpace} {A X D Y : SpaceOver B} (f : MapOver A X) (g : MapOver D Y)
    (z : (fiberProductOver A D).space) :
    ((fiberProductMap f g).map z).val = (f.map z.val.1, g.map z.val.2) := by
  rfl

/-- A point of the kified fiber product, retaining the common-base equation. -/
def fiberPair {B : KSpace} {X Y : SpaceOver B} (x : X.space) (y : Y.space)
    (h : X.projection x = Y.projection y) : (fiberProductOver X Y).space :=
  ⟨(x, y), h⟩

/-- A group object in K/B, with continuous unit, multiplication, and inverse
and all group axioms on each common fiber (PDF pp. 2, 5--6). -/
structure ParametrizedGroup (B : KSpace) where
  total : SpaceOver B
  unit : C(B, total.space)
  unit_over : ∀ b, total.projection (unit b) = b
  multiply : MapOver (fiberProductOver total total) total
  inverse : MapOver total total
  left_unit : ∀ g, multiply.map
    (fiberPair (unit (total.projection g)) g (unit_over _)) = g
  right_unit : ∀ g, multiply.map
    (fiberPair g (unit (total.projection g)) (unit_over _).symm) = g
  left_inverse : ∀ g, multiply.map
    (fiberPair (inverse.map g) g (inverse.over_base g)) = unit (total.projection g)
  right_inverse : ∀ g, multiply.map
    (fiberPair g (inverse.map g) (inverse.over_base g).symm) = unit (total.projection g)
  associative : ∀ g h k (hgh : total.projection g = total.projection h)
    (hhk : total.projection h = total.projection k),
    multiply.map (fiberPair (multiply.map (fiberPair g h hgh)) k
      ((multiply.over_base (fiberPair g h hgh)).trans (hgh.trans hhk))) =
    multiply.map (fiberPair g (multiply.map (fiberPair h k hhk))
      (hgh.trans (multiply.over_base (fiberPair h k hhk)).symm))

/-- Sanity: every base admits the trivial parametrized group, whose fibers
are singletons. This also covers the empty base. -/
example (B : KSpace) : Nonempty (ParametrizedGroup B) := by
  let T : SpaceOver B := ⟨B, ContinuousMap.id B⟩
  let m : MapOver (fiberProductOver T T) T :=
    { map := (⟨fun z : FiberProductSet T T => z.val.1, by fun_prop⟩ :
        C(FiberProductSet T T, B)).comp (kifyProjection (FiberProductSet T T))
      over_base := fun _ => rfl }
  exact ⟨{ total := T
           unit := ContinuousMap.id B
           unit_over := fun _ => rfl
           multiply := m
           inverse := identityOver T
           left_unit := fun _ => rfl
           right_unit := fun _ => rfl
           left_inverse := fun _ => rfl
           right_inverse := fun _ => rfl
           associative := fun _ _ _ _ _ => rfl }⟩

/-- A continuous right action over B; its domain is a kified fiber product,
not the Cartesian product of possibly different fibers (PDF p. 6). -/
structure EquivariantSpace {B : KSpace} (G : ParametrizedGroup B) where
  total : SpaceOver B
  action : MapOver (fiberProductOver total G.total) total
  action_unit : ∀ x, action.map
    (fiberPair x (G.unit (total.projection x)) (G.unit_over _).symm) = x
  action_multiply : ∀ x g h (hxg : total.projection x = G.total.projection g)
    (hgh : G.total.projection g = G.total.projection h),
    action.map (fiberPair (action.map (fiberPair x g hxg)) h
      ((action.over_base (fiberPair x g hxg)).trans (hxg.trans hgh))) =
    action.map (fiberPair x (G.multiply.map (fiberPair g h hgh))
      (hxg.trans (G.multiply.over_base (fiberPair g h hgh)).symm))

/-- A G-equivariant map over B (PDF p. 6). -/
structure EquivariantMap {B : KSpace} {G : ParametrizedGroup B}
    (X Y : EquivariantSpace G) where
  map : MapOver X.total Y.total
  equivariant : ∀ x g (h : X.total.projection x = G.total.projection g),
    map.map (X.action.map (fiberPair x g h)) =
    Y.action.map (fiberPair (map.map x) g ((map.over_base x).trans h))

/-- Identity G-map. -/
def equivariantIdentity {B : KSpace} {G : ParametrizedGroup B}
    (X : EquivariantSpace G) : EquivariantMap X X where
  map := identityOver X.total
  equivariant := fun _ _ _ => rfl

/-- Composite G-map in functional order. -/
def equivariantCompose {B : KSpace} {G : ParametrizedGroup B}
    {X Y Z : EquivariantSpace G} (g : EquivariantMap Y Z) (f : EquivariantMap X Y) :
    EquivariantMap X Z where
  map := composeOver g.map f.map
  equivariant := by
    intro x a h
    change g.map.map (f.map.map (X.action.map (fiberPair x a h))) = _
    rw [f.equivariant, g.equivariant]
    rfl

/-- A G-map X tensor I to Y. Equivariance is required at every time,
with G acting trivially on I, and the homotopy stays over B (PDF pp. 6--7). -/
structure EquivariantCylinderMap {B : KSpace} {G : ParametrizedGroup B}
    (X Y : EquivariantSpace G) where
  map : C(kify (X.total.space × unitInterval), Y.total.space)
  over_base : ∀ x t, Y.total.projection (map (x, t)) = X.total.projection x
  equivariant : ∀ x g (h : X.total.projection x = G.total.projection g) t,
    map (X.action.map (fiberPair x g h), t) =
    Y.action.map (fiberPair (map (x, t)) g ((over_base x t).trans h))

/-- Homotopy through G-maps over B with the specified endpoints (PDF p. 7). -/
def EquivariantlyHomotopic {B : KSpace} {G : ParametrizedGroup B}
    {X Y : EquivariantSpace G} (f g : EquivariantMap X Y) : Prop :=
  ∃ H : EquivariantCylinderMap X Y,
    (∀ x, H.map (x, 0) = f.map.map x) ∧
    ∀ x, H.map (x, 1) = g.map.map x

/-- An equivariant f-equivalence includes an equivariant inverse and both
homotopies over B (PDF p. 7). -/
def IsEquivariantFEquivalence {B : KSpace} {G : ParametrizedGroup B}
    {X Y : EquivariantSpace G} (f : EquivariantMap X Y) : Prop :=
  ∃ g : EquivariantMap Y X,
    EquivariantlyHomotopic (equivariantCompose g f) (equivariantIdentity X) ∧
    EquivariantlyHomotopic (equivariantCompose f g) (equivariantIdentity Y)

/-- The equivariant covering homotopy property for every G-space over B
(PDF p. 7). -/
def IsEquivariantFFibration {B : KSpace} {G : ParametrizedGroup B}
    {X Y : EquivariantSpace G} (p : EquivariantMap X Y) : Prop :=
  ∀ (Z : EquivariantSpace G) (a : EquivariantMap Z X)
    (H : EquivariantCylinderMap Z Y),
    (∀ z, H.map (z, 0) = p.map.map (a.map.map z)) →
    ∃ L : EquivariantCylinderMap Z X,
      (∀ z, L.map (z, 0) = a.map.map z) ∧
      ∀ z t, p.map.map (L.map (z, t)) = H.map (z, t)

/-- The LLP in G K/B against all equivariant f-acyclic f-fibrations
(PDF p. 7). This is stronger than a condition only on underlying maps. -/
def IsEquivariantStrongFCofibration {B : KSpace} {G : ParametrizedGroup B}
    {A X : EquivariantSpace G} (i : EquivariantMap A X) : Prop :=
  ∀ (U V : EquivariantSpace G) (p : EquivariantMap U V),
    IsEquivariantFFibration p → IsEquivariantFEquivalence p →
    ∀ (a : EquivariantMap A U) (b : EquivariantMap X V),
      (∀ z, p.map.map (a.map.map z) = b.map.map (i.map.map z)) →
      ∃ l : EquivariantMap X U,
        (∀ z, l.map.map (i.map.map z) = a.map.map z) ∧
        ∀ x, p.map.map (l.map.map x) = b.map.map x

/-- The source's right-equivariant fiberwise NDR condition (PDF pp. 5, 7).
The zero set is exactly A, A is fixed for all times, and only u(x) < 1
requires the terminal homotopy value to lie in A. -/
def IsEquivariantFiberwiseNDR {B : KSpace} {G : ParametrizedGroup B}
    (X : EquivariantSpace G) (A : Set X.total.space) : Prop :=
  ∃ u : C(X.total.space, unitInterval),
    ∃ H : EquivariantCylinderMap X X,
      (∀ x, x ∈ A ↔ u x = 0) ∧
      (∀ x, H.map (x, 0) = x) ∧
      (∀ x ∈ A, ∀ t, H.map (x, t) = x) ∧
      (∀ x, (u x : ℝ) < 1 → H.map (x, 1) ∈ A) ∧
      ∀ x g (h : X.total.projection x = G.total.projection g),
        u (X.action.map (fiberPair x g h)) = u x

/-- Sanity: the identity G-map satisfies the equivariant LLP. -/
example {B : KSpace} {G : ParametrizedGroup B} (X : EquivariantSpace G) :
    IsEquivariantStrongFCofibration (equivariantIdentity X) := by
  intro U V p hp he a b h
  exact ⟨a, fun _ => rfl, h⟩

/-- Sanity: the whole space is an NDR subspace, using u = 0 and the
constant-in-time equivariant fiberwise homotopy. -/
example {B : KSpace} {G : ParametrizedGroup B} (X : EquivariantSpace G) :
    IsEquivariantFiberwiseNDR X Set.univ := by
  let H : EquivariantCylinderMap X X :=
    { map := ContinuousMap.fst.comp (kifyProjection (X.total.space × unitInterval))
      over_base := fun _ _ => rfl
      equivariant := fun _ _ _ _ => rfl }
  refine ⟨ContinuousMap.const _ 0, H, ?_, ?_, ?_, ?_, ?_⟩
  · intro x
    simp
  · intro x
    rfl
  · intro x hx t
    rfl
  · intro x hx
    trivial
  · intro x g h
    rfl

/-- A continuous homomorphism of parametrized groups (PDF pp. 2, 8).
Preservation of inverses follows from these group homomorphism axioms. -/
structure GroupMapOver {B : KSpace} (G H : ParametrizedGroup B) where
  map : MapOver G.total H.total
  unit_preserved : ∀ b, map.map (G.unit b) = H.unit b
  multiply_preserved : ∀ g h (e : G.total.projection g = G.total.projection h),
    map.map (G.multiply.map (fiberPair g h e)) =
    H.multiply.map (fiberPair (map.map g) (map.map h)
      ((map.over_base g).trans (e.trans (map.over_base h).symm)))

/-- A simplicial parametrized group is contravariant functor data on the
whole simplex category, taking every arrow to a continuous homomorphism.
The identity and composition equations specify the full simplicial object;
levels are not arbitrary unrelated groups (PDF p. 2). -/
structure SimplicialParametrizedGroup (B : KSpace) where
  obj : SimplexCategoryᵒᵖ → ParametrizedGroup B
  map : ∀ {a b : SimplexCategoryᵒᵖ}, (a ⟶ b) → GroupMapOver (obj a) (obj b)
  map_identity : ∀ (a : SimplexCategoryᵒᵖ) (x : (obj a).total.space),
    (map (𝟙 a)).map.map x = x
  map_composition : ∀ {a b c : SimplexCategoryᵒᵖ} (f : a ⟶ b) (g : b ⟶ c)
    (x : (obj a).total.space),
    (map (f ≫ g)).map.map x =
      (map g).map.map ((map f).map.map x)

/-- The constant simplicial parametrized group, for a sanity check. -/
def constantSimplicialGroup {B : KSpace} (G : ParametrizedGroup B) :
    SimplicialParametrizedGroup B where
  obj := fun _ => G
  map := fun _ =>
    { map := identityOver G.total
      unit_preserved := fun _ => rfl
      multiply_preserved := fun _ _ _ => rfl }
  map_identity := fun _ _ => rfl
  map_composition := fun _ _ _ => rfl

/-- The terminal object B→B, which is the domain of the identity section. -/
def baseOver (B : KSpace) : SpaceOver B := ⟨B, ContinuousMap.id B⟩

/-- The canonical identity section as a map over B (PDF pp. 5--6). -/
def groupUnitSection {B : KSpace} (G : ParametrizedGroup B) :
    MapOver (baseOver B) G.total where
  map := G.unit
  over_base := G.unit_over

/-- Well-sectionedness is the strong cofibration property of the canonical
identity section, not an arbitrary supplied section (Definition 6, PDF p. 6). -/
def IsWellSectioned {B : KSpace} (G : ParametrizedGroup B) : Prop :=
  IsStrongFCofibration (groupUnitSection G)

/-- Goodness requires every degeneracy in every degree to be a strong
fbar-cofibration (Definition 20, PDF p. 12). -/
def IsGoodSimplicialGroup {B : KSpace} (G : SimplicialParametrizedGroup B) : Prop :=
  ∀ (n : ℕ) (i : Fin (n + 1)),
    IsStrongFCofibration ((G.map (SimplexCategory.σ i).op).map)

/-- Sanity: every degeneracy of the constant simplicial group is exactly
the identity on the given group, including degree zero. -/
example {B : KSpace} (G : ParametrizedGroup B) (n : ℕ) (i : Fin (n + 1))
    (x : G.total.space) :
    (((constantSimplicialGroup G).map (SimplexCategory.σ i).op).map.map x) = x := by
  rfl

end QAlgorithms.Papers.Independent.Intakethird100.P73
Source
Simplicial principal bundles in parametrized spaces, arXiv:1203.2460v4, https://arxiv.org/abs/1203.2460v4
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What the Lean code literally says, in plain math · gpt-6.1-sol

QAlgorithms.Papers.Independent.Intakethird100.P73.EquivariantCylinderMap

Let BBB be a compactly generated topological space, GGG a parametrized group over BBB, and X,YX,YX,Y right GGG-spaces over BBB. Explicitly, the total spaces are compactly generated; their projections are continuous; GGG has a continuous unit section and inverse and fiberwise group multiplication; and X,YX,YX,Y have projection-preserving right actions satisfying the unit and associativity laws. Multiplication and actions are continuous on the kifications of their same-fiber pair spaces. For any space TTT, write K(T)K(T)K(T) for its underlying set with the topology in which UUU is open exactly when every continuous map from a compact Hausdorff space into TTT has open inverse image of UUU. An equivariant cylinder map from XXX to YYY consists of a continuous function

H:K(X×[0,1])⟶YH:K(X\times[0,1])\longrightarrow YH:K(X×[0,1])⟶Y

such that, for every x∈Xx\in Xx∈X and t∈[0,1]t\in[0,1]t∈[0,1], pY(H(x,t))=pX(x)p_Y(H(x,t))=p_X(x)pY​(H(x,t))=pX​(x), and, for every g∈EGg\in E_Gg∈EG​ with pX(x)=pG(g)p_X(x)=p_G(g)pX​(x)=pG​(g),

H(x⋅g,t)=H(x,t)⋅g.H(x\cdot g,t)=H(x,t)\cdot g.H(x⋅g,t)=H(x,t)⋅g.

No endpoint values are prescribed. Empty spaces and empty fibers are permitted.

QAlgorithms.Papers.Independent.Intakethird100.P73.EquivariantMap

Let BBB be a compactly generated topological space, and let GGG be a parametrized group over BBB: its compactly generated total space EGE_GEG​ has a projection pG:EG→Bp_G:E_G\to BpG​:EG​→B, a continuous unit section, a continuous inverse preserving the projection, and multiplication on pairs in the same fiber, continuous on the kification of that fiber product, satisfying the group laws in every fiber. Here kification keeps the underlying set and declares a subset open exactly when its inverse image under every continuous map from a compact Hausdorff space into the original space is open. Let XXX and YYY be compactly generated spaces with continuous projections pX,pYp_X,p_YpX​,pY​ to BBB and right GGG-actions preserving these projections, continuous on the kified fiber products, and satisfying the unit and action associativity laws. An equivariant map from XXX to YYY consists of a continuous function f:X→Yf:X\to Yf:X→Y such that pY(f(x))=pX(x)p_Y(f(x))=p_X(x)pY​(f(x))=pX​(x) for every xxx, together with the requirement

f(x⋅g)=f(x)⋅gfor every x∈X, g∈EG with pX(x)=pG(g).f(x\cdot g)=f(x)\cdot g \qquad \text{for every }x\in X,\ g\in E_G \text{ with }p_X(x)=p_G(g).f(x⋅g)=f(x)⋅gfor every x∈X, g∈EG​ with pX​(x)=pG​(g).

The spaces and their fibers need not be nonempty; conditions quantified over empty domains are vacuous.

QAlgorithms.Papers.Independent.Intakethird100.P73.EquivariantSpace

For any compactly generated topological space BBB, fix a parametrized group GGG consisting of a compactly generated space EEE with continuous projection πE:E→B\pi_E:E\to BπE​:E→B, a continuous section e:B→Ee:B\to Ee:B→E, a continuous multiplication m:κ(E×BE)→Em:\kappa(E\times_B E)\to Em:κ(E×B​E)→E preserving the common projection, and a continuous inverse map ι:E→E\iota:E\to Eι:E→E preserving projection, with m(e(πE(g)),g)=m(g,e(πE(g)))=gm(e(\pi_E(g)),g)=m(g,e(\pi_E(g)))=gm(e(πE​(g)),g)=m(g,e(πE​(g)))=g, m(ι(g),g)=m(g,ι(g))=e(πE(g))m(\iota(g),g)=m(g,\iota(g))=e(\pi_E(g))m(ι(g),g)=m(g,ι(g))=e(πE​(g)) for every g∈Eg\in Eg∈E, and m(m(g,h),k)=m(g,m(h,k))m(m(g,h),k)=m(g,m(h,k))m(m(g,h),k)=m(g,m(h,k)) whenever πE(g)=πE(h)=πE(k)\pi_E(g)=\pi_E(h)=\pi_E(k)πE​(g)=πE​(h)=πE​(k); here πE(e(b))=b\pi_E(e(b))=bπE​(e(b))=b for every b∈Bb\in Bb∈B. For this fixed GGG, the structure consists of a compactly generated topological space XXX with a continuous projection πX:X→B\pi_X:X\to BπX​:X→B and a continuous action α:κ(X×BE)→X\alpha:\kappa(X\times_B E)\to Xα:κ(X×B​E)→X satisfying πX(α(x,g))=πX(x)\pi_X(\alpha(x,g))=\pi_X(x)πX​(α(x,g))=πX​(x) for every pair with πX(x)=πE(g)\pi_X(x)=\pi_E(g)πX​(x)=πE​(g), together with the identities

α(x,e(πX(x)))=x\alpha(x,e(\pi_X(x)))=xα(x,e(πX​(x)))=x

for every x∈Xx\in Xx∈X, and

α(α(x,g),h)=α(x,m(g,h))\alpha(\alpha(x,g),h)=\alpha(x,m(g,h))α(α(x,g),h)=α(x,m(g,h))

for every x∈Xx\in Xx∈X and g,h∈Eg,h\in Eg,h∈E with πX(x)=πE(g)\pi_X(x)=\pi_E(g)πX​(x)=πE​(g) and πE(g)=πE(h)\pi_E(g)=\pi_E(h)πE​(g)=πE​(h). In this description, E×BE={(g,h):πE(g)=πE(h)}E\times_B E=\{(g,h):\pi_E(g)=\pi_E(h)\}E×B​E={(g,h):πE​(g)=πE​(h)} and X×BE={(x,g):πX(x)=πE(g)}X\times_B E=\{(x,g):\pi_X(x)=\pi_E(g)\}X×B​E={(x,g):πX​(x)=πE​(g)}, initially with their ordinary product subspace topologies; for either such space TTT, κT\kappa TκT has the same underlying set with U⊆TU\subseteq TU⊆T open exactly when s−1(U)s^{-1}(U)s−1(U) is open for every compact Hausdorff space SSS in the fixed universe and every originally continuous map s:S→Ts:S\to Ts:S→T. Each multiplication or action is evaluated on a pair together with the required equality of projections. The space XXX may be empty, in which case its action identities are vacuous.

QAlgorithms.Papers.Independent.Intakethird100.P73.EquivariantlyHomotopic

Let BBB be a compactly generated topological space, GGG a parametrized group over BBB, and X,YX,YX,Y compactly generated right GGG-spaces over BBB. This means that GGG has continuous projection, unit section and inverse and fiberwise group laws, while X,YX,YX,Y have continuous projections and projection-preserving, unital, associative right actions; multiplication and actions are continuous on their kified fiber products. Write K(T)K(T)K(T) for the same set as TTT, with a subset open exactly when its inverse image under every continuous compact Hausdorff probe into TTT is open. For any continuous projection-preserving, action-preserving maps f,g:X→Yf,g:X\to Yf,g:X→Y, the assertion that they are equivariantly homotopic means that there exists a continuous

H:K(X×[0,1])⟶YH:K(X\times[0,1])\longrightarrow YH:K(X×[0,1])⟶Y

such that, for every x∈Xx\in Xx∈X and t∈[0,1]t\in[0,1]t∈[0,1],

H(x,0)=f(x),H(x,1)=g(x),pY(H(x,t))=pX(x),H(x,0)=f(x),\qquad H(x,1)=g(x),\qquad p_Y(H(x,t))=p_X(x),H(x,0)=f(x),H(x,1)=g(x),pY​(H(x,t))=pX​(x),

and H(x⋅a,t)=H(x,t)⋅aH(x\cdot a,t)=H(x,t)\cdot aH(x⋅a,t)=H(x,t)⋅a for every a∈EGa\in E_Ga∈EG​ with pX(x)=pG(a)p_X(x)=p_G(a)pX​(x)=pG​(a). No nonemptiness is assumed; if XXX is empty, all the pointwise conditions are vacuous and the empty function supplies such a homotopy.

QAlgorithms.Papers.Independent.Intakethird100.P73.FiberProductSet

For any compactly generated topological space BBB and any compactly generated topological spaces X,YX,YX,Y equipped with continuous projections πX:X→B\pi_X:X\to BπX​:X→B and πY:Y→B\pi_Y:Y\to BπY​:Y→B, this abbreviation denotes the subtype

{(x,y)∈X×Y:πX(x)=πY(y)}.\{(x,y)\in X\times Y:\pi_X(x)=\pi_Y(y)\}.{(x,y)∈X×Y:πX​(x)=πY​(y)}.

An element consists of a pair together with evidence that its two coordinates have equal projections. This subtype may be empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.FiberwiseHomotopic

For any compactly generated topological space BBB, compactly generated topological spaces X,YX,YX,Y with continuous projections πX:X→B\pi_X:X\to BπX​:X→B, πY:Y→B\pi_Y:Y\to BπY​:Y→B, and continuous maps f,g:X→Yf,g:X\to Yf,g:X→Y satisfying πY∘f=πX=πY∘g\pi_Y\circ f=\pi_X=\pi_Y\circ gπY​∘f=πX​=πY​∘g, this predicate means that there exists a continuous map H:κ(X×I)→YH:\kappa(X\times I)\to YH:κ(X×I)→Y, where I=[0,1]I=[0,1]I=[0,1] has its usual topology and κ(X×I)\kappa(X\times I)κ(X×I) has the same underlying set as the ordinary product, with a subset UUU open exactly when s−1(U)s^{-1}(U)s−1(U) is open for every compact Hausdorff space SSS in the fixed universe and every continuous map s:S→X×Is:S\to X\times Is:S→X×I for the ordinary product topology, such that

H(x,0)=f(x),H(x,1)=g(x),πY(H(x,t))=πX(x)H(x,0)=f(x),\qquad H(x,1)=g(x),\qquad \pi_Y(H(x,t))=\pi_X(x)H(x,0)=f(x),H(x,1)=g(x),πY​(H(x,t))=πX​(x)

for every x∈Xx\in Xx∈X and every t∈It\in It∈I. There is no nonemptiness assumption on XXX; if XXX is empty, the conditions are satisfied by the empty map.

QAlgorithms.Papers.Independent.Intakethird100.P73.GroupMapOver

Let BBB be a compactly generated topological space and let G,HG,HG,H be parametrized groups over BBB. Thus their compactly generated total spaces EG,EHE_G,E_HEG​,EH​ have continuous projections pG,pHp_G,p_HpG​,pH​, continuous unit sections eG,eHe_G,e_HeG​,eH​ satisfying pG(eG(b))=pH(eH(b))=bp_G(e_G(b))=p_H(e_H(b))=bpG​(eG​(b))=pH​(eH​(b))=b, continuous inverses preserving the projections, and multiplications defined on same-fiber pairs and satisfying the group laws in every fiber. These multiplications are continuous on the kifications of the fiber products, where kification declares a subset open exactly when its inverse image under every continuous map from a compact Hausdorff space into the original space is open. A group map over BBB from GGG to HHH consists of a continuous f:EG→EHf:E_G\to E_Hf:EG​→EH​ such that, for every g∈EGg\in E_Gg∈EG​, pH(f(g))=pG(g)p_H(f(g))=p_G(g)pH​(f(g))=pG​(g), and such that

f(eG(b))=eH(b)(b∈B),f(gh)=f(g)f(h)(g,h∈EG, pG(g)=pG(h)).f(e_G(b))=e_H(b)\quad(b\in B),\qquad f(gh)=f(g)f(h)\quad \bigl(g,h\in E_G,\ p_G(g)=p_G(h)\bigr).f(eG​(b))=eH​(b)(b∈B),f(gh)=f(g)f(h)(g,h∈EG​, pG​(g)=pG​(h)).

Preservation of inverses is not a separate field of the structure. The base may be empty; if it is nonempty, each group fiber contains its specified unit.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsEquivariantFEquivalence

Let BBB be a compactly generated topological space and GGG a parametrized group over BBB: its compactly generated total space has continuous projection, unit section and inverse, with group multiplication in each fiber continuous on the kified fiber product. Let X,YX,YX,Y be compactly generated spaces over BBB carrying projection-preserving right GGG-actions, continuous on the kified fiber products and satisfying the unit and associativity laws. For a space TTT, let K(T)K(T)K(T) have the same underlying set, with subsets open precisely when all continuous maps from compact Hausdorff spaces into TTT have open inverse images. A continuous projection-preserving, action-preserving map f:X→Yf:X\to Yf:X→Y is an equivariant FFF-equivalence exactly when there exist a continuous projection-preserving, action-preserving map g:Y→Xg:Y\to Xg:Y→X and continuous maps

HX:K(X×[0,1])→X,HY:K(Y×[0,1])→YH_X:K(X\times[0,1])\to X,\qquad H_Y:K(Y\times[0,1])\to YHX​:K(X×[0,1])→X,HY​:K(Y×[0,1])→Y

with

HX(x,0)=g(f(x)),HX(x,1)=x,HY(y,0)=f(g(y)),HY(y,1)=y.H_X(x,0)=g(f(x)),\quad H_X(x,1)=x,\qquad H_Y(y,0)=f(g(y)),\quad H_Y(y,1)=y.HX​(x,0)=g(f(x)),HX​(x,1)=x,HY​(y,0)=f(g(y)),HY​(y,1)=y.

For all points and all t∈[0,1]t\in[0,1]t∈[0,1], these maps preserve the base point and satisfy HX(x⋅a,t)=HX(x,t)⋅aH_X(x\cdot a,t)=H_X(x,t)\cdot aHX​(x⋅a,t)=HX​(x,t)⋅a and HY(y⋅a,t)=HY(y,t)⋅aH_Y(y\cdot a,t)=H_Y(y,t)\cdot aHY​(y⋅a,t)=HY​(y,t)⋅a whenever the indicated point and group element lie over the same base point. Neither uniqueness nor nonemptiness is required.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsEquivariantFFibration

Let BBB be a compactly generated topological space, GGG a parametrized group over BBB, and p:X→Yp:X\to Yp:X→Y a continuous projection-preserving, action-preserving map between compactly generated right GGG-spaces over BBB. Here the group has continuous projection, unit section and inverse and fiberwise group laws, the actions preserve projections and satisfy the unit and associativity laws, and multiplication and actions are continuous on the kified same-fiber pair spaces. Write K(T)K(T)K(T) for the topology on the underlying set of TTT whose open subsets are those having open inverse image under every continuous compact Hausdorff probe into TTT. The assertion that ppp is an equivariant FFF-fibration means the following: for every such right GGG-space ZZZ, every continuous projection-preserving, action-preserving map a:Z→Xa:Z\to Xa:Z→X, and every continuous map H:K(Z×[0,1])→YH:K(Z\times[0,1])\to YH:K(Z×[0,1])→Y satisfying

pY(H(z,t))=pZ(z),H(z⋅g,t)=H(z,t)⋅g,H(z,0)=p(a(z)),p_Y(H(z,t))=p_Z(z),\qquad H(z\cdot g,t)=H(z,t)\cdot g,\qquad H(z,0)=p(a(z)),pY​(H(z,t))=pZ​(z),H(z⋅g,t)=H(z,t)⋅g,H(z,0)=p(a(z)),

where the action identity is required for all z,gz,gz,g over the same base point and all t∈[0,1]t\in[0,1]t∈[0,1], there exists a continuous L:K(Z×[0,1])→XL:K(Z\times[0,1])\to XL:K(Z×[0,1])→X satisfying, for all z,tz,tz,t,

pX(L(z,t))=pZ(z),L(z,0)=a(z),p(L(z,t))=H(z,t),p_X(L(z,t))=p_Z(z),\qquad L(z,0)=a(z),\qquad p(L(z,t))=H(z,t),pX​(L(z,t))=pZ​(z),L(z,0)=a(z),p(L(z,t))=H(z,t),

and L(z⋅g,t)=L(z,t)⋅gL(z\cdot g,t)=L(z,t)\cdot gL(z⋅g,t)=L(z,t)⋅g for all compatible z,g,tz,g,tz,g,t. Empty test spaces are included; the lift is not required to be unique.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsEquivariantFiberwiseNDR

Let BBB be a compactly generated topological space, GGG a parametrized group over BBB, XXX a compactly generated right GGG-space over BBB, and AAA any subset of XXX. Explicitly, GGG has continuous projection, unit section and inverse and fiberwise group multiplication, while XXX has a continuous projection pXp_XpX​ and a projection-preserving, unital, associative right action; multiplication and action are continuous on the kified fiber products. Let K(T)K(T)K(T) denote the same set as TTT, with subsets open exactly when their inverse images under every continuous compact Hausdorff probe into TTT are open. The assertion that X,AX,AX,A satisfy the equivariant fiberwise NDR condition means that there exist a continuous function u:X→[0,1]u:X\to[0,1]u:X→[0,1] and a continuous map H:K(X×[0,1])→XH:K(X\times[0,1])\to XH:K(X×[0,1])→X such that pX(H(x,t))=pX(x)p_X(H(x,t))=p_X(x)pX​(H(x,t))=pX​(x) for all x,tx,tx,t, and H(x⋅g,t)=H(x,t)⋅gH(x\cdot g,t)=H(x,t)\cdot gH(x⋅g,t)=H(x,t)⋅g for every compatible x,gx,gx,g and every ttt, with

x∈A ⟺ u(x)=0,H(x,0)=x,H(x,t)=x for x∈A,u(x)<1 ⟹ H(x,1)∈A,x\in A\ \Longleftrightarrow\ u(x)=0,\qquad H(x,0)=x,\qquad H(x,t)=x\ \text{for }x\in A,\qquad u(x)<1\ \Longrightarrow\ H(x,1)\in A,x∈A ⟺ u(x)=0,H(x,0)=x,H(x,t)=x for x∈A,u(x)<1 ⟹ H(x,1)∈A,

and u(x⋅g)=u(x)u(x\cdot g)=u(x)u(x⋅g)=u(x) for every x,gx,gx,g over the same base point. The endpoint inclusion is required only where u(x)<1u(x)<1u(x)<1. The subset AAA is not separately assumed closed or invariant, and empty XXX and empty AAA are allowed.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsEquivariantStrongFCofibration

Let BBB be a compactly generated topological space, GGG a parametrized group over BBB, and i:A→Xi:A\to Xi:A→X a continuous projection-preserving, action-preserving map of compactly generated right GGG-spaces over BBB. The group has continuous projection, unit section and inverse and fiberwise group laws; the right actions preserve projections and satisfy the unit and associativity laws; multiplication and actions are continuous on kified fiber products. Write K(T)K(T)K(T) for the same set as TTT, with UUU open exactly when every continuous compact Hausdorff probe into TTT has open inverse image of UUU. In this paragraph an equivariant map means a continuous map preserving the projection and satisfying f(x⋅g)=f(x)⋅gf(x\cdot g)=f(x)\cdot gf(x⋅g)=f(x)⋅g for compatible pairs; an equivariant homotopy from fff to ggg means a continuous H:K(D×[0,1])→EH:K(D\times[0,1])\to EH:K(D×[0,1])→E preserving the projection and the action at every time, with H(d,0)=f(d)H(d,0)=f(d)H(d,0)=f(d) and H(d,1)=g(d)H(d,1)=g(d)H(d,1)=g(d). The assertion that iii is an equivariant strong FFF-cofibration means that for every pair U,VU,VU,V of these right GGG-spaces and every equivariant p:U→Vp:U\to Vp:U→V having both of the following properties—every equivariant a0:Z→Ua_0:Z\to Ua0​:Z→U and equivariant homotopy H:K(Z×[0,1])→VH:K(Z\times[0,1])\to VH:K(Z×[0,1])→V with H(z,0)=p(a0(z))H(z,0)=p(a_0(z))H(z,0)=p(a0​(z)), for every right GGG-space ZZZ, admit an equivariant homotopy LLL with L(z,0)=a0(z)L(z,0)=a_0(z)L(z,0)=a0​(z) and p(L(z,t))=H(z,t)p(L(z,t))=H(z,t)p(L(z,t))=H(z,t); and there exists an equivariant q:V→Uq:V\to Uq:V→U with equivariant homotopies from q∘pq\circ pq∘p to id⁡U\operatorname{id}_UidU​ and from p∘qp\circ qp∘q to id⁡V\operatorname{id}_VidV​—every pair of equivariant maps a:A→Ua:A\to Ua:A→U, b:X→Vb:X\to Vb:X→V satisfying p(a(z))=b(i(z))p(a(z))=b(i(z))p(a(z))=b(i(z)) for all z∈Az\in Az∈A admits an equivariant map ℓ:X→U\ell:X\to Uℓ:X→U such that

ℓ(i(z))=a(z)(z∈A),p(ℓ(x))=b(x)(x∈X).\ell(i(z))=a(z)\quad(z\in A),\qquad p(\ell(x))=b(x)\quad(x\in X).ℓ(i(z))=a(z)(z∈A),p(ℓ(x))=b(x)(x∈X).

Neither injectivity of iii nor uniqueness of ℓ\ellℓ is part of this definition, and empty spaces are included.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsFEquivalence

For any compactly generated topological space BBB, compactly generated topological spaces X,YX,YX,Y with continuous projections πX:X→B\pi_X:X\to BπX​:X→B, πY:Y→B\pi_Y:Y\to BπY​:Y→B, and continuous map f:X→Yf:X\to Yf:X→Y satisfying πY∘f=πX\pi_Y\circ f=\pi_XπY​∘f=πX​, this predicate means that there exist a continuous map g:Y→Xg:Y\to Xg:Y→X satisfying πX∘g=πY\pi_X\circ g=\pi_YπX​∘g=πY​ and continuous maps HX:κ(X×I)→XH_X:\kappa(X\times I)\to XHX​:κ(X×I)→X and HY:κ(Y×I)→YH_Y:\kappa(Y\times I)\to YHY​:κ(Y×I)→Y, where I=[0,1]I=[0,1]I=[0,1], such that

HX(x,0)=g(f(x)),HX(x,1)=x,πX(HX(x,t))=πX(x),HY(y,0)=f(g(y)),HY(y,1)=y,πY(HY(y,t))=πY(y)\begin{aligned} H_X(x,0)&=g(f(x)),& H_X(x,1)&=x,& \pi_X(H_X(x,t))&=\pi_X(x),\\ H_Y(y,0)&=f(g(y)),& H_Y(y,1)&=y,& \pi_Y(H_Y(y,t))&=\pi_Y(y) \end{aligned}HX​(x,0)HY​(y,0)​=g(f(x)),=f(g(y)),​HX​(x,1)HY​(y,1)​=x,=y,​πX​(HX​(x,t))πY​(HY​(y,t))​=πX​(x),=πY​(y)​

for all x∈Xx\in Xx∈X, y∈Yy\in Yy∈Y, and t∈It\in It∈I. Here, for either ordinary product T=X×IT=X\times IT=X×I or T=Y×IT=Y\times IT=Y×I, κT\kappa TκT has the same set as TTT, with U⊆TU\subseteq TU⊆T open exactly when s−1(U)s^{-1}(U)s−1(U) is open for every compact Hausdorff space SSS in the fixed universe and every continuous map s:S→Ts:S\to Ts:S→T. The inverse and homotopies are required to exist but are not required to be unique; empty spaces are included in the quantification.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsFFibration

For any compactly generated topological space BBB, compactly generated topological spaces X,YX,YX,Y with continuous projections πX:X→B\pi_X:X\to BπX​:X→B, πY:Y→B\pi_Y:Y\to BπY​:Y→B, and continuous map p:X→Yp:X\to Yp:X→Y satisfying πY∘p=πX\pi_Y\circ p=\pi_XπY​∘p=πX​, this predicate states the following lifting property. For every compactly generated topological space ZZZ with continuous projection πZ:Z→B\pi_Z:Z\to BπZ​:Z→B, every continuous map a:Z→Xa:Z\to Xa:Z→X satisfying πX∘a=πZ\pi_X\circ a=\pi_ZπX​∘a=πZ​, and every continuous map H:κ(Z×I)→YH:\kappa(Z\times I)\to YH:κ(Z×I)→Y, where I=[0,1]I=[0,1]I=[0,1], if

πY(H(z,t))=πZ(z)for all z∈Z, t∈I,H(z,0)=p(a(z))for all z∈Z,\pi_Y(H(z,t))=\pi_Z(z)\quad\text{for all }z\in Z,\ t\in I, \qquad H(z,0)=p(a(z))\quad\text{for all }z\in Z,πY​(H(z,t))=πZ​(z)for all z∈Z, t∈I,H(z,0)=p(a(z))for all z∈Z,

then there exists a continuous map L:κ(Z×I)→XL:\kappa(Z\times I)\to XL:κ(Z×I)→X such that

πX(L(z,t))=πZ(z),L(z,0)=a(z),p(L(z,t))=H(z,t)\pi_X(L(z,t))=\pi_Z(z),\qquad L(z,0)=a(z),\qquad p(L(z,t))=H(z,t)πX​(L(z,t))=πZ​(z),L(z,0)=a(z),p(L(z,t))=H(z,t)

for every z∈Zz\in Zz∈Z and t∈It\in It∈I. Here κ(Z×I)\kappa(Z\times I)κ(Z×I) has the ordinary product’s underlying set, with UUU open exactly when s−1(U)s^{-1}(U)s−1(U) is open for every compact Hausdorff space SSS in the fixed universe and every continuous map s:S→Z×Is:S\to Z\times Is:S→Z×I for the ordinary product topology. The quantification includes empty ZZZ, for which the lifting conditions hold for the empty map.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsGoodSimplicialGroup

For a compactly generated space BBB and a simplicial parametrized group GGG over BBB, this defines a property of every degeneracy map si:Gn→Gn+1s_i:G_n\to G_{n+1}si​:Gn​→Gn+1​, for every integer n≥0n\geq0n≥0 and every i∈{0,…,n}i\in\{0,\ldots,n\}i∈{0,…,n}. Here GGG assigns a parametrized group to each object of the opposite simplex category and a continuous map over BBB preserving units and multiplication to each morphism, preserving identities and composition pointwise; each degree has a compactly generated total space En→BE_n\to BEn​→B, a continuous unit section, continuous inversion over BBB, and continuous multiplication on the compactly generated replacement of the pairs in the same fiber, satisfying the group laws in each fiber. The map sis_isi​ is assigned to the opposite of the order-preserving surjection [n+1]→[n][n+1]\to[n][n+1]→[n] that identifies iii and i+1i+1i+1. Write I=[0,1]I=[0,1]I=[0,1], and let k(T)k(T)k(T) retain the underlying set of TTT with the finest topology making every originally continuous map from a compact Hausdorff space in the same universe continuous. A map over BBB is continuous and commutes with projections, and a homotopy over BBB from f0:S→Tf_0:S\to Tf0​:S→T to f1:S→Tf_1:S\to Tf1​:S→T is a continuous F:k(S×I)→TF:k(S\times I)\to TF:k(S×I)→T with endpoints f0,f1f_0,f_1f0​,f1​ and πT(F(s,t))=πS(s)\pi_T(F(s,t))=\pi_S(s)πT​(F(s,t))=πS​(s). The required property is that, for every n,in,in,i, every pair of compactly generated spaces U,VU,VU,V over BBB, and every map p:U→Vp:U\to Vp:U→V over BBB satisfying the following two conditions, every commuting square with left side sis_isi​ has a lift. The first condition on ppp is that, for every compactly generated space ZZZ over BBB, map c:Z→Uc:Z\to Uc:Z→U over BBB, and continuous H:k(Z×I)→VH:k(Z\times I)\to VH:k(Z×I)→V with πV(H(z,t))=πZ(z)\pi_V(H(z,t))=\pi_Z(z)πV​(H(z,t))=πZ​(z) and H(z,0)=p(c(z))H(z,0)=p(c(z))H(z,0)=p(c(z)), there is a continuous L:k(Z×I)→UL:k(Z\times I)\to UL:k(Z×I)→U with πU(L(z,t))=πZ(z)\pi_U(L(z,t))=\pi_Z(z)πU​(L(z,t))=πZ​(z), L(z,0)=c(z)L(z,0)=c(z)L(z,0)=c(z), and p(L(z,t))=H(z,t)p(L(z,t))=H(z,t)p(L(z,t))=H(z,t) for all z,tz,tz,t. The second condition is that some map q:V→Uq:V\to Uq:V→U over BBB admits homotopies over BBB from q∘pq\circ pq∘p to idU\mathrm{id}_UidU​ and from p∘qp\circ qp∘q to idV\mathrm{id}_VidV​. Explicitly, every pair of maps a:En→Ua:E_n\to Ua:En​→U and b:En+1→Vb:E_{n+1}\to Vb:En+1​→V over BBB with p(a(x))=b(si(x))p(a(x))=b(s_i(x))p(a(x))=b(si​(x)) for every x∈Enx\in E_nx∈En​ must admit a map ℓ:En+1→U\ell:E_{n+1}\to Uℓ:En+1​→U over BBB with ℓ(si(x))=a(x)\ell(s_i(x))=a(x)ℓ(si​(x))=a(x) for every x∈Enx\in E_nx∈En​ and p(ℓ(y))=b(y)p(\ell(y))=b(y)p(ℓ(y))=b(y) for every y∈En+1y\in E_{n+1}y∈En+1​. The quantifiers include n=0n=0n=0, where i=0i=0i=0, and impose no nonemptiness assumptions.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsStrongFCofibration

For any compactly generated topological space BBB, compactly generated topological spaces A,XA,XA,X with continuous projections πA:A→B\pi_A:A\to BπA​:A→B, πX:X→B\pi_X:X\to BπX​:X→B, and continuous map i:A→Xi:A\to Xi:A→X satisfying πX∘i=πA\pi_X\circ i=\pi_AπX​∘i=πA​, this predicate states that the following holds for every pair of compactly generated topological spaces U,VU,VU,V with continuous projections πU:U→B\pi_U:U\to BπU​:U→B, πV:V→B\pi_V:V\to BπV​:V→B, and every continuous map p:U→Vp:U\to Vp:U→V satisfying πV∘p=πU\pi_V\circ p=\pi_UπV​∘p=πU​. Suppose, first, that for every compactly generated space ZZZ with continuous projection πZ:Z→B\pi_Z:Z\to BπZ​:Z→B, every continuous c:Z→Uc:Z\to Uc:Z→U with πU∘c=πZ\pi_U\circ c=\pi_ZπU​∘c=πZ​, and every continuous H:κ(Z×I)→VH:\kappa(Z\times I)\to VH:κ(Z×I)→V satisfying πV(H(z,t))=πZ(z)\pi_V(H(z,t))=\pi_Z(z)πV​(H(z,t))=πZ​(z) and H(z,0)=p(c(z))H(z,0)=p(c(z))H(z,0)=p(c(z)), there exists a continuous L:κ(Z×I)→UL:\kappa(Z\times I)\to UL:κ(Z×I)→U satisfying πU(L(z,t))=πZ(z)\pi_U(L(z,t))=\pi_Z(z)πU​(L(z,t))=πZ​(z), L(z,0)=c(z)L(z,0)=c(z)L(z,0)=c(z), and p(L(z,t))=H(z,t)p(L(z,t))=H(z,t)p(L(z,t))=H(z,t), for all z∈Z,t∈Iz\in Z,t\in Iz∈Z,t∈I. Suppose, second, that there exist a continuous q:V→Uq:V\to Uq:V→U with πU∘q=πV\pi_U\circ q=\pi_VπU​∘q=πV​ and continuous maps KU:κ(U×I)→UK_U:\kappa(U\times I)\to UKU​:κ(U×I)→U, KV:κ(V×I)→VK_V:\kappa(V\times I)\to VKV​:κ(V×I)→V satisfying KU(u,0)=q(p(u))K_U(u,0)=q(p(u))KU​(u,0)=q(p(u)), KU(u,1)=uK_U(u,1)=uKU​(u,1)=u, πU(KU(u,t))=πU(u)\pi_U(K_U(u,t))=\pi_U(u)πU​(KU​(u,t))=πU​(u), KV(v,0)=p(q(v))K_V(v,0)=p(q(v))KV​(v,0)=p(q(v)), KV(v,1)=vK_V(v,1)=vKV​(v,1)=v, and πV(KV(v,t))=πV(v)\pi_V(K_V(v,t))=\pi_V(v)πV​(KV​(v,t))=πV​(v), for all u∈U,v∈V,t∈Iu\in U,v\in V,t\in Iu∈U,v∈V,t∈I. Under these two suppositions, for every continuous a:A→Ua:A\to Ua:A→U and b:X→Vb:X\to Vb:X→V satisfying πU∘a=πA\pi_U\circ a=\pi_AπU​∘a=πA​, πV∘b=πX\pi_V\circ b=\pi_XπV​∘b=πX​, and p(a(z))=b(i(z))p(a(z))=b(i(z))p(a(z))=b(i(z)) for all z∈Az\in Az∈A, there exists a continuous l:X→Ul:X\to Ul:X→U satisfying

πU(l(x))=πX(x),l(i(z))=a(z),p(l(x))=b(x)\pi_U(l(x))=\pi_X(x),\qquad l(i(z))=a(z),\qquad p(l(x))=b(x)πU​(l(x))=πX​(x),l(i(z))=a(z),p(l(x))=b(x)

for all z∈A,x∈Xz\in A,x\in Xz∈A,x∈X. Throughout, I=[0,1]I=[0,1]I=[0,1], and κ(T×I)\kappa(T\times I)κ(T×I) denotes the ordinary product’s underlying set with WWW open exactly when s−1(W)s^{-1}(W)s−1(W) is open for every compact Hausdorff space SSS in the fixed universe and every ordinarily continuous s:S→T×Is:S\to T\times Is:S→T×I. All quantified spaces may be empty, and the requirement on a particular ppp is conditional on both suppositions holding.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsWeaklyHausdorff

For a KSpace BBB, meaning a type in universe uuu equipped with a compactly generated topology, this defines the property that, for every compact Hausdorff space SSS in universe uuu and every continuous map f:S→Bf:S\to Bf:S→B, the image f(S)={f(s)∣s∈S}f(S)=\{f(s)\mid s\in S\}f(S)={f(s)∣s∈S} is closed in BBB. Empty compact Hausdorff domains are included, in which case the image is empty; the property also permits BBB itself to be empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.IsWellSectioned

For a compactly generated space BBB and a parametrized group GGG over BBB, with compactly generated total space EEE, continuous projection π:E→B\pi:E\to Bπ:E→B, continuous unit section e:B→Ee:B\to Ee:B→E, continuous fiberwise inversion, and continuous fiberwise multiplication satisfying the group laws, this defines the following property of eee. Write I=[0,1]I=[0,1]I=[0,1], and write k(T)k(T)k(T) for the underlying set of a topological space TTT equipped with the finest topology making every originally continuous map from a compact Hausdorff space in the same universe continuous; in particular, the multiplication of GGG is continuous on k({(g,h)∈E×E:π(g)=π(h)})k(\{(g,h)\in E\times E:\pi(g)=\pi(h)\})k({(g,h)∈E×E:π(g)=π(h)}). A map over BBB means a continuous map commuting with the specified projections to BBB, and a homotopy over BBB from f0:S→Tf_0:S\to Tf0​:S→T to f1:S→Tf_1:S\to Tf1​:S→T means a continuous F:k(S×I)→TF:k(S\times I)\to TF:k(S×I)→T such that F(s,0)=f0(s)F(s,0)=f_0(s)F(s,0)=f0​(s), F(s,1)=f1(s)F(s,1)=f_1(s)F(s,1)=f1​(s), and πT(F(s,t))=πS(s)\pi_T(F(s,t))=\pi_S(s)πT​(F(s,t))=πS​(s) for all s,ts,ts,t. The property is that, for every pair of compactly generated spaces U,VU,VU,V over BBB and every map p:U→Vp:U\to Vp:U→V over BBB satisfying both of the following conditions, every commuting square with left side eee has a lift: first, for every compactly generated space ZZZ over BBB, every map c:Z→Uc:Z\to Uc:Z→U over BBB, and every continuous H:k(Z×I)→VH:k(Z\times I)\to VH:k(Z×I)→V with πV(H(z,t))=πZ(z)\pi_V(H(z,t))=\pi_Z(z)πV​(H(z,t))=πZ​(z) and H(z,0)=p(c(z))H(z,0)=p(c(z))H(z,0)=p(c(z)), there exists a continuous L:k(Z×I)→UL:k(Z\times I)\to UL:k(Z×I)→U with πU(L(z,t))=πZ(z)\pi_U(L(z,t))=\pi_Z(z)πU​(L(z,t))=πZ​(z), L(z,0)=c(z)L(z,0)=c(z)L(z,0)=c(z), and p(L(z,t))=H(z,t)p(L(z,t))=H(z,t)p(L(z,t))=H(z,t) for all z,tz,tz,t; second, there exists a map q:V→Uq:V\to Uq:V→U over BBB with homotopies over BBB from q∘pq\circ pq∘p to idU\mathrm{id}_UidU​ and from p∘qp\circ qp∘q to idV\mathrm{id}_VidV​. Explicitly, for every map a:B→Ua:B\to Ua:B→U over BBB and every map b:E→Vb:E\to Vb:E→V over BBB such that p(a(s))=b(e(s))p(a(s))=b(e(s))p(a(s))=b(e(s)) for every s∈Bs\in Bs∈B, there must exist a map ℓ:E→U\ell:E\to Uℓ:E→U over BBB such that ℓ(e(s))=a(s)\ell(e(s))=a(s)ℓ(e(s))=a(s) for every s∈Bs\in Bs∈B and p(ℓ(x))=b(x)p(\ell(x))=b(x)p(ℓ(x))=b(x) for every x∈Ex\in Ex∈E. No nonemptiness assumptions are imposed.

QAlgorithms.Papers.Independent.Intakethird100.P73.KSpace

A KSpace consists of a type XXX in universe uuu, a topology on XXX, and a proof that XXX with that topology is compactly generated. The underlying type is allowed to be empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.MapOver

For every base BBB equipped with a compactly generated topology and every two spaces over it, consisting of compactly generated spaces EX,EYE_X,E_YEX​,EY​ with continuous projections pX:EX→Bp_X:E_X\to BpX​:EX​→B and pY:EY→Bp_Y:E_Y\to BpY​:EY​→B, a MapOver from the first to the second consists of a continuous map f:EX→EYf:E_X\to E_Yf:EX​→EY​ and a proof that pY(f(x))=pX(x)p_Y(f(x))=p_X(x)pY​(f(x))=pX​(x) for every x∈EXx\in E_Xx∈EX​. When EXE_XEX​ is empty, this equality condition is vacuous.

QAlgorithms.Papers.Independent.Intakethird100.P73.ParametrizedGroup

For a compactly generated topological space BBB, this structure consists of a compactly generated topological space EEE with a continuous projection π:E→B\pi:E\to Bπ:E→B; a continuous map e:B→Ee:B\to Ee:B→E satisfying π(e(b))=b\pi(e(b))=bπ(e(b))=b for every b∈Bb\in Bb∈B; a continuous multiplication m:κP→Em:\kappa P\to Em:κP→E, where P={(g,h)∈E×E:π(g)=π(h)}P=\{(g,h)\in E\times E:\pi(g)=\pi(h)\}P={(g,h)∈E×E:π(g)=π(h)}, satisfying π(m(g,h))=π(g)\pi(m(g,h))=\pi(g)π(m(g,h))=π(g) for every (g,h)∈P(g,h)\in P(g,h)∈P; and a continuous map ι:E→E\iota:E\to Eι:E→E satisfying π(ι(g))=π(g)\pi(\iota(g))=\pi(g)π(ι(g))=π(g) for every g∈Eg\in Eg∈E. Here PPP initially carries the product subspace topology, and κP\kappa PκP has the same underlying set, with U⊆PU\subseteq PU⊆P open exactly when s−1(U)s^{-1}(U)s−1(U) is open for every compact Hausdorff space SSS in the fixed universe and every continuous map s:S→Ps:S\to Ps:S→P for that subspace topology. These data must satisfy

m(e(π(g)),g)=g,m(g,e(π(g)))=g,m(ι(g),g)=e(π(g)),m(g,ι(g))=e(π(g))m(e(\pi(g)),g)=g,\qquad m(g,e(\pi(g)))=g,\qquad m(\iota(g),g)=e(\pi(g)),\qquad m(g,\iota(g))=e(\pi(g))m(e(π(g)),g)=g,m(g,e(π(g)))=g,m(ι(g),g)=e(π(g)),m(g,ι(g))=e(π(g))

for every g∈Eg\in Eg∈E, and

m(m(g,h),k)=m(g,m(h,k))m(m(g,h),k)=m(g,m(h,k))m(m(g,h),k)=m(g,m(h,k))

for every g,h,k∈Eg,h,k\in Eg,h,k∈E with π(g)=π(h)\pi(g)=\pi(h)π(g)=π(h) and π(h)=π(k)\pi(h)=\pi(k)π(h)=π(k). Each occurrence of mmm is applied to the indicated pair together with the equality of its projections. The section eee supplies an element in every fiber over a point of BBB; the base BBB itself is allowed to be empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.SimplicialParametrizedGroup

For a compactly generated topological space BBB, a simplicial parametrized group over BBB consists of a parametrized group GaG_aGa​ over BBB for every object aaa of the opposite simplex category, and a group map over BBB, denoted G(α):Ga→GbG(\alpha):G_a\to G_bG(α):Ga​→Gb​, for every arrow α:a→b\alpha:a\to bα:a→b in that category. The simplex category has the nonempty finite ordered sets [n]={0,…,n}[n]=\{0,\ldots,n\}[n]={0,…,n}, for all natural numbers nnn, including n=0n=0n=0, and order-preserving maps; taking its opposite reverses the arrows. Each GaG_aGa​ has a compactly generated total space EaE_aEa​, continuous projection pa:Ea→Bp_a:E_a\to Bpa​:Ea​→B, continuous unit section and inverse, and fiberwise group multiplication continuous on the kified fiber product and satisfying the group laws. Here kification gives the original underlying set the topology whose open subsets have open inverse image under every continuous compact Hausdorff probe into the original space. Each G(α)G(\alpha)G(α) is continuous, preserves the projection to BBB, sends each fiber unit to the corresponding fiber unit, and preserves products of elements lying in the same fiber. The required identity and composition laws are the pointwise equalities

G(id⁡a)(x)=x(a, x∈Ea),G(β∘α)(x)=G(β)(G(α)(x))G(\operatorname{id}_a)(x)=x \quad(a,\ x\in E_a), \qquad G(\beta\circ\alpha)(x)=G(\beta)(G(\alpha)(x))G(ida​)(x)=x(a, x∈Ea​),G(β∘α)(x)=G(β)(G(α)(x))

for every triple of objects a,b,ca,b,ca,b,c, every α:a→b\alpha:a\to bα:a→b, every β:b→c\beta:b\to cβ:b→c, and every x∈Eax\in E_ax∈Ea​. The base is not required to be nonempty.

QAlgorithms.Papers.Independent.Intakethird100.P73.SpaceOver

For every base BBB that is a type in universe uuu equipped with a compactly generated topology, a SpaceOver BBB consists of another type EEE in universe uuu equipped with a compactly generated topology and a continuous map p:E→Bp:E\to Bp:E→B. The total space EEE may be empty; if BBB is empty, the existence of ppp forces EEE to be empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.baseOver

For every compactly generated space BBB, this defines a space over BBB whose total space is BBB itself and whose continuous projection to BBB is the identity b↦bb\mapsto bb↦b. There is no nonemptiness assumption on BBB.

QAlgorithms.Papers.Independent.Intakethird100.P73.composeOver

For any compactly generated topological space BBB, let X,Y,ZX,Y,ZX,Y,Z be compactly generated topological spaces with continuous projections πX:X→B\pi_X:X\to BπX​:X→B, πY:Y→B\pi_Y:Y\to BπY​:Y→B, and πZ:Z→B\pi_Z:Z\to BπZ​:Z→B. Given continuous maps f:X→Yf:X\to Yf:X→Y and g:Y→Zg:Y\to Zg:Y→Z satisfying πY(f(x))=πX(x)\pi_Y(f(x))=\pi_X(x)πY​(f(x))=πX​(x) for every x∈Xx\in Xx∈X and πZ(g(y))=πY(y)\pi_Z(g(y))=\pi_Y(y)πZ​(g(y))=πY​(y) for every y∈Yy\in Yy∈Y, this definition gives the continuous map g∘f:X→Zg\circ f:X\to Zg∘f:X→Z over BBB, whose value at xxx is g(f(x))g(f(x))g(f(x)) and whose projection satisfies πZ(g(f(x)))=πX(x)\pi_Z(g(f(x)))=\pi_X(x)πZ​(g(f(x)))=πX​(x).

QAlgorithms.Papers.Independent.Intakethird100.P73.constantSimplicialGroup

For any compactly generated space BBB and parametrized group GGG over BBB, this defines a constant simplicial parametrized group. Here GGG consists of a compactly generated total space EEE, a continuous projection π:E→B\pi:E\to Bπ:E→B, a continuous unit section e:B→Ee:B\to Ee:B→E with π(e(b))=b\pi(e(b))=bπ(e(b))=b, a continuous inverse over BBB, and a multiplication over BBB defined on the compactly generated replacement of {(g,h)∈E×E:π(g)=π(h)}\{(g,h)\in E\times E:\pi(g)=\pi(h)\}{(g,h)∈E×E:π(g)=π(h)}, satisfying the unit, inverse, and associativity laws in each fiber. The compactly generated replacement retains the underlying set and uses the finest topology making every originally continuous map from a compact Hausdorff space in the same universe continuous. The constructed simplicial object assigns this same GGG to every object of the opposite simplex category and assigns the identity map of EEE, over BBB and preserving units and multiplication, to every morphism. Its identity and composition laws hold pointwise because all these maps are identities.

QAlgorithms.Papers.Independent.Intakethird100.P73.equivariantCompose

Let BBB be a compactly generated topological space and GGG a parametrized group over BBB, meaning a compactly generated total space with a continuous projection to BBB, continuous unit section and inverse, and fiberwise group multiplication continuous on the kified fiber product. Let X,Y,ZX,Y,ZX,Y,Z be compactly generated spaces over BBB with projection-preserving right GGG-actions satisfying the unit and associativity laws and continuous on the corresponding kified fiber products. Kification gives a space the topology in which a subset is open exactly when its inverse image under every continuous compact Hausdorff probe into the original space is open. For any continuous projection-preserving, action-preserving maps f:X→Yf:X\to Yf:X→Y and g:Y→Zg:Y\to Zg:Y→Z, this defines their equivariant composite g∘f:X→Zg\circ f:X\to Zg∘f:X→Z by

(g∘f)(x)=g(f(x)).(g\circ f)(x)=g(f(x)).(g∘f)(x)=g(f(x)).

It preserves the projection, pZ(g(f(x)))=pX(x)p_Z(g(f(x)))=p_X(x)pZ​(g(f(x)))=pX​(x), and for every x∈Xx\in Xx∈X and a∈EGa\in E_Ga∈EG​ with pX(x)=pG(a)p_X(x)=p_G(a)pX​(x)=pG​(a), it satisfies g(f(x⋅a))=g(f(x))⋅ag(f(x\cdot a))=g(f(x))\cdot ag(f(x⋅a))=g(f(x))⋅a. No nonemptiness assumptions are imposed.

QAlgorithms.Papers.Independent.Intakethird100.P73.equivariantIdentity

For every compactly generated topological space BBB, every parametrized group GGG over BBB, and every right GGG-space XXX over BBB, this defines the equivariant identity map X→XX\to XX→X by x↦xx\mapsto xx↦x. Explicitly, GGG has a compactly generated total space over BBB, a continuous unit section and inverse, and fiberwise group multiplication continuous on the kified fiber product; XXX is compactly generated with a continuous projection pX:X→Bp_X:X\to BpX​:X→B and a projection-preserving right action satisfying the unit and associativity laws and continuous on the kified same-fiber pairs. Kification means that a subset is open precisely when every continuous map from a compact Hausdorff space into the original space has open inverse image of that subset. The defined map is continuous, satisfies pX(x)=pX(x)p_X(x)=p_X(x)pX​(x)=pX​(x), and preserves the action because

id⁡X(x⋅g)=id⁡X(x)⋅g\operatorname{id}_X(x\cdot g)=\operatorname{id}_X(x)\cdot gidX​(x⋅g)=idX​(x)⋅g

for every x,gx,gx,g lying over the same point of BBB. This definition also applies when BBB or XXX is empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.fiberPair

For any compactly generated topological space BBB, compactly generated topological spaces X,YX,YX,Y with continuous projections πX:X→B\pi_X:X\to BπX​:X→B, πY:Y→B\pi_Y:Y\to BπY​:Y→B, points x∈Xx\in Xx∈X, y∈Yy\in Yy∈Y, and evidence hhh that πX(x)=πY(y)\pi_X(x)=\pi_Y(y)πX​(x)=πY​(y), this definition returns the element represented by (x,y)(x,y)(x,y), together with that evidence, in the space whose underlying set is P={(x′,y′)∈X×Y:πX(x′)=πY(y′)}P=\{(x',y')\in X\times Y:\pi_X(x')=\pi_Y(y')\}P={(x′,y′)∈X×Y:πX​(x′)=πY​(y′)}. Its topology is the compactly generated refinement of the ordinary product subspace topology: U⊆PU\subseteq PU⊆P is open exactly when s−1(U)s^{-1}(U)s−1(U) is open for every compact Hausdorff space SSS in the fixed universe and every map s:S→Ps:S\to Ps:S→P continuous for that subspace topology. Its projection to BBB sends (x′,y′)(x',y')(x′,y′) to πX(x′)\pi_X(x')πX​(x′).

QAlgorithms.Papers.Independent.Intakethird100.P73.fiberProductMap

For any compactly generated topological space BBB, let A,X,D,YA,X,D,YA,X,D,Y be compactly generated topological spaces with continuous projections πA,πX,πD,πY\pi_A,\pi_X,\pi_D,\pi_YπA​,πX​,πD​,πY​ to BBB, and let f:A→Xf:A\to Xf:A→X and g:D→Yg:D\to Yg:D→Y be continuous maps satisfying πX∘f=πA\pi_X\circ f=\pi_AπX​∘f=πA​ and πY∘g=πD\pi_Y\circ g=\pi_DπY​∘g=πD​. Put P={(a,d)∈A×D:πA(a)=πD(d)}P=\{(a,d)\in A\times D:\pi_A(a)=\pi_D(d)\}P={(a,d)∈A×D:πA​(a)=πD​(d)} and Q={(x,y)∈X×Y:πX(x)=πY(y)}Q=\{(x,y)\in X\times Y:\pi_X(x)=\pi_Y(y)\}Q={(x,y)∈X×Y:πX​(x)=πY​(y)}, initially with their product subspace topologies. For either such space TTT, write κT\kappa TκT for the same set with the topology in which U⊆TU\subseteq TU⊆T is open exactly when s−1(U)s^{-1}(U)s−1(U) is open for every compact Hausdorff space SSS in the fixed universe and every originally continuous map s:S→Ts:S\to Ts:S→T. This definition gives the continuous map over BBB

κP⟶κQ,(a,d)⟼(f(a),g(d)).\kappa P\longrightarrow\kappa Q,\qquad(a,d)\longmapsto(f(a),g(d)).κP⟶κQ,(a,d)⟼(f(a),g(d)).

The projections of these spaces to BBB are respectively (a,d)↦πA(a)(a,d)\mapsto\pi_A(a)(a,d)↦πA​(a) and (x,y)↦πX(x)(x,y)\mapsto\pi_X(x)(x,y)↦πX​(x), and preservation of the projection is the equality πX(f(a))=πA(a)\pi_X(f(a))=\pi_A(a)πX​(f(a))=πA​(a).

QAlgorithms.Papers.Independent.Intakethird100.P73.fiberProductOver

For any compactly generated topological space BBB and compactly generated topological spaces X,YX,YX,Y with continuous projections πX:X→B\pi_X:X\to BπX​:X→B and πY:Y→B\pi_Y:Y\to BπY​:Y→B, form P={(x,y)∈X×Y:πX(x)=πY(y)}P=\{(x,y)\in X\times Y:\pi_X(x)=\pi_Y(y)\}P={(x,y)∈X×Y:πX​(x)=πY​(y)}, initially with the subspace topology inherited from the product. This definition gives a space over BBB whose underlying set is PPP, whose topology is its compactly generated refinement, and whose continuous projection sends (x,y)(x,y)(x,y) to πX(x)\pi_X(x)πX​(x). Explicitly, a subset U⊆PU\subseteq PU⊆P is open in this refined topology exactly when s−1(U)s^{-1}(U)s−1(U) is open for every compact Hausdorff space SSS in the fixed universe and every map s:S→Ps:S\to Ps:S→P continuous for the original subspace topology. The projection is the original first-coordinate projection composed with the continuous identity map from this refined space to the original PPP. The construction also applies when PPP is empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.fiberProductSetMap

For any compactly generated topological space BBB, let A,X,D,YA,X,D,YA,X,D,Y be compactly generated topological spaces with continuous projections πA,πX,πD,πY\pi_A,\pi_X,\pi_D,\pi_YπA​,πX​,πD​,πY​ to BBB. Given continuous maps f:A→Xf:A\to Xf:A→X and g:D→Yg:D\to Yg:D→Y satisfying πX(f(a))=πA(a)\pi_X(f(a))=\pi_A(a)πX​(f(a))=πA​(a) for every a∈Aa\in Aa∈A and πY(g(d))=πD(d)\pi_Y(g(d))=\pi_D(d)πY​(g(d))=πD​(d) for every d∈Dd\in Dd∈D, this definition gives the continuous map

{(a,d)∈A×D:πA(a)=πD(d)}⟶{(x,y)∈X×Y:πX(x)=πY(y)},(a,d)⟼(f(a),g(d)),\{(a,d)\in A\times D:\pi_A(a)=\pi_D(d)\} \longrightarrow \{(x,y)\in X\times Y:\pi_X(x)=\pi_Y(y)\}, \qquad (a,d)\longmapsto(f(a),g(d)),{(a,d)∈A×D:πA​(a)=πD​(d)}⟶{(x,y)∈X×Y:πX​(x)=πY​(y)},(a,d)⟼(f(a),g(d)),

where both subtypes carry their ordinary product subspace topologies. Membership of the output follows from πX(f(a))=πA(a)=πD(d)=πY(g(d))\pi_X(f(a))=\pi_A(a)=\pi_D(d)=\pi_Y(g(d))πX​(f(a))=πA​(a)=πD​(d)=πY​(g(d)).

QAlgorithms.Papers.Independent.Intakethird100.P73.groupUnitSection

For every compactly generated space BBB and parametrized group GGG over BBB, this defines a continuous map over BBB from BBB, equipped with its identity projection, to the total space EEE of GGG. A parametrized group here has a continuous projection π:E→B\pi:E\to Bπ:E→B from a compactly generated total space, a continuous unit section e:B→Ee:B\to Ee:B→E, continuous inversion over BBB, and continuous multiplication over BBB on the compactly generated replacement of the space of pairs in the same fiber, with the group laws holding in each fiber. That replacement retains the underlying set and uses the finest topology making every originally continuous map from a compact Hausdorff space in the same universe continuous. The defined map is exactly b↦e(b)b\mapsto e(b)b↦e(b); the condition that it is over BBB is the given equality π(e(b))=b\pi(e(b))=bπ(e(b))=b for every b∈Bb\in Bb∈B.

QAlgorithms.Papers.Independent.Intakethird100.P73.identityOver

For every base BBB equipped with a compactly generated topology and every space over it, consisting of a compactly generated space EEE and a continuous projection p:E→Bp:E\to Bp:E→B, this defines a map from that space over BBB to itself whose underlying continuous function is id⁡E\operatorname{id}_EidE​. Its required compatibility with the projection is p(id⁡E(x))=p(x)p(\operatorname{id}_E(x))=p(x)p(idE​(x))=p(x) for every x∈Ex\in Ex∈E; the construction also applies when EEE is empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.kSpaceCoeSort

This instance allows any KSpace—a type in universe uuu equipped with a compactly generated topology—to be used as a type, in which case it denotes its underlying carrier type.

QAlgorithms.Papers.Independent.Intakethird100.P73.kSpaceCompactlyGenerated

For every KSpace XXX, consisting of a carrier type equipped with a topology and a proof of compact generation, this instance supplies the fact that the underlying type with its stored topology is compactly generated, using the proof stored in XXX.

QAlgorithms.Papers.Independent.Intakethird100.P73.kSpaceTopology

For every KSpace XXX, consisting of a carrier type, a topology, and a proof that this topology is compactly generated, this instance equips the underlying type of XXX with exactly the topology stored in XXX.

QAlgorithms.Papers.Independent.Intakethird100.P73.kify

For every type XXX in universe uuu equipped with a topology, this defines a KSpace with underlying type XXX and the following topology: a subset U⊆XU\subseteq XU⊆X is open precisely when f−1(U)f^{-1}(U)f−1(U) is open for every compact Hausdorff space SSS in universe uuu and every map f:S→Xf:S\to Xf:S→X continuous for the original topology on XXX. Equivalently, this is the final topology of the evaluation map from the disjoint union of all such domains indexed by pairs (S,f)(S,f)(S,f), sending the point indexed by (S,f,s)(S,f,s)(S,f,s) to f(s)f(s)f(s). The construction includes a proof that this topology is compactly generated and applies also when XXX is empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.kifyMap

For every pair of types X,YX,YX,Y in universe uuu, each equipped with a topology, and every continuous map f:X→Yf:X\to Yf:X→Y, this defines a continuous map with underlying function fff after replacing both topologies as follows: for either space ZZZ, a subset U⊆ZU\subseteq ZU⊆Z is open in the replacement topology exactly when g−1(U)g^{-1}(U)g−1(U) is open for every compact Hausdorff space SSS in universe uuu and every map g:S→Zg:S\to Zg:S→Z continuous for the original topology. The construction includes empty spaces whenever the supplied map fff exists.

QAlgorithms.Papers.Independent.Intakethird100.P73.kifyProbe

For every type XXX in universe uuu equipped with a topology, every compact Hausdorff space SSS in universe uuu, and every continuous map f:S→Xf:S\to Xf:S→X, this defines a continuous map with the same underlying function fff from SSS to the underlying set XXX equipped with the topology in which U⊆XU\subseteq XU⊆X is open exactly when g−1(U)g^{-1}(U)g−1(U) is open for every compact Hausdorff space TTT in universe uuu and every originally continuous map g:T→Xg:T\to Xg:T→X. Empty domains are included; if XXX is empty, the given function fff can exist only when SSS is empty.

QAlgorithms.Papers.Independent.Intakethird100.P73.kifyProjection

For every type XXX in universe uuu equipped with a topology T\mathcal TT, this defines a continuous map whose underlying function is the identity on XXX, from XXX equipped with the topology in which UUU is open exactly when f−1(U)f^{-1}(U)f−1(U) is open for every compact Hausdorff space SSS in universe uuu and every T\mathcal TT-continuous map f:S→Xf:S\to Xf:S→X, to XXX equipped with its original topology T\mathcal TT. No nonemptiness assumption on XXX is imposed.

Human review
  • Endorsed by Shuze Chen · Nov 1, 2026

    Confirmed by the moderator at approval.

  • Endorsed by Gohan · Nov 1, 2026

    Confirmed by the mission captain (proposal self-audit).

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