Stable filtering and scaling of a chosen color class
ProvedThreeSum.LightClassFilter.meets3sumalgorithmsfine-grained-complexitythree-sum-1962word-ram
Let memory contain integer values at and colors at , for . Fix a desired color , integer scale with , and natural with . Assume , both input arrays end at or before , and .
If the Light program contains the class-filter body, its call on these parameters terminates within steps. For the list , in increasing input-index order, the result satisfies
Memory outside is preserved.
This constructs the selected color-class array with its stored length.
Preamble
/- Copyright (c) 2026 Anthropic, PBC. All rights reserved. Released under Apache 2.0 license as described in the file LICENSE. SPDX-License-Identifier: Apache-2.0 -/ import Definitions.Def_APSPSource_RemainingDefinitions import Definitions.Def_APSPSource_ThreeSumApsp_Lang_Logic import Definitions.Def_APSPSource_ThreeSumApsp_Lang_Regions import Definitions.Def_APSPSource_ThreeSumApsp_Lang_Syntax import Definitions.Def_ThreeSum1962Source_Bundle01 import Definitions.Def_ThreeSum1962Source_Bundle02 import Mathlib.Algebra.BigOperators.Fin import Mathlib.Algebra.BigOperators.Group.Finset.Basic import Mathlib.Algebra.Group.Int.Defs import Mathlib.Algebra.GroupWithZero.Nat import Mathlib.Algebra.Order.BigOperators.Group.List import Mathlib.Algebra.Order.BigOperators.Group.Multiset import Mathlib.Algebra.Order.Field.Basic import Mathlib.Algebra.Order.Group.Abs import Mathlib.Algebra.Order.Group.Int import Mathlib.Algebra.Order.Group.Nat import Mathlib.Algebra.Order.Group.Unbundled.Abs import Mathlib.Algebra.Order.Ring.Abs import Mathlib.Algebra.Order.Ring.Int import Mathlib.Data.Int.Cast.Lemmas import Mathlib.Data.Int.Notation import Mathlib.Data.List.GetD import Mathlib.Data.Nat.Cast.Order.Ring import Mathlib.Data.Nat.Count import Mathlib.Data.Nat.Notation import Mathlib.Data.Nat.SuccPred import Mathlib.LinearAlgebra.Matrix.Defs import Mathlib.Logic.Function.Basic import Mathlib.Order.ConditionallyCompleteLattice.Basic import Mathlib.Tactic.GCongr import Mathlib.Tactic.Linarith import Mathlib.Tactic.NormNum import Mathlib.Tactic.Positivity import Mathlib.Tactic.Ring import Theorems.Thm_Light_Ends_for import Theorems.Thm_Light_seg_append import Theorems.Thm_Light_seg_cons set_option autoImplicit false set_option relaxedAutoImplicit false set_option Elab.async false namespace Light end Light namespace ThreeSumApsp end ThreeSumApsp
Formal statement
theorem ThreeSum.LightClassFilter.meets : ∀ {lim : Light.Limits} {P : Light.Program} {d p src colors dst n want U : Nat} {scale : Int} {μ : Nat → Int}
(hmain :
@Eq.{1} (Option.{0} Light.Stmt)
(@GetElem?.getElem?.{0, 0, 0} Light.Program Nat Light.Stmt
(fun (as : List.{0} Light.Stmt) (i : Nat) => @LT.lt.{0} Nat instLTNat i (@List.length.{0} Light.Stmt as))
(@List.instGetElem?NatLtLength.{0} Light.Stmt) P p)
(@Option.some.{0} Light.Stmt ThreeSum.LightClassFilter.body))
(x : Nat → Int) (color : Nat → Nat)
(hw : @LE.le.{0} Int Int.instLEInt (@Nat.cast.{0} Int instNatCastInt lim.space) lim.word)
(h3 : @LE.le.{0} Int Int.instLEInt (@OfNat.ofNat.{0} Int (nat_lit 3) (@instOfNat (nat_lit 3))) lim.word)
(hsrc : @LE.le.{0} Nat instLENat (@HAdd.hAdd.{0, 0, 0} Nat Nat Nat (@instHAdd.{0} Nat instAddNat) src n) dst)
(hcolors : @LE.le.{0} Nat instLENat (@HAdd.hAdd.{0, 0, 0} Nat Nat Nat (@instHAdd.{0} Nat instAddNat) colors n) dst)
(hspace :
@LE.le.{0} Nat instLENat
(@HAdd.hAdd.{0, 0, 0} Nat Nat Nat (@instHAdd.{0} Nat instAddNat) dst
(@HAdd.hAdd.{0, 0, 0} Nat Nat Nat (@instHAdd.{0} Nat instAddNat) n
(@OfNat.ofNat.{0} Nat (nat_lit 1) (instOfNatNat (nat_lit 1)))))
lim.space)
(hwant : @LT.lt.{0} Nat instLTNat want (@OfNat.ofNat.{0} Nat (nat_lit 3) (instOfNatNat (nat_lit 3))))
(hscale :
@LE.le.{0} Int Int.instLEInt (@abs.{0} Int instLatticeInt Int.instAddGroup scale)
(@OfNat.ofNat.{0} Int (nat_lit 1) (@instOfNat (nat_lit 1))))
(hU : @LE.le.{0} Int Int.instLEInt (@Nat.cast.{0} Int instNatCastInt U) lim.word)
(hread :
∀ (i : Nat),
@LT.lt.{0} Nat instLTNat i n →
@Eq.{1} Int (μ (@HAdd.hAdd.{0, 0, 0} Nat Nat Nat (@instHAdd.{0} Nat instAddNat) src i)) (x i))
(hcolorRead :
∀ (i : Nat),
@LT.lt.{0} Nat instLTNat i n →
@Eq.{1} Int (μ (@HAdd.hAdd.{0, 0, 0} Nat Nat Nat (@instHAdd.{0} Nat instAddNat) colors i))
(@Nat.cast.{0} Int instNatCastInt (color i)))
(hcolorLt :
∀ (i : Nat),
@LT.lt.{0} Nat instLTNat i n →
@LT.lt.{0} Nat instLTNat (color i) (@OfNat.ofNat.{0} Nat (nat_lit 3) (instOfNatNat (nat_lit 3))))
(hbound :
∀ (i : Nat),
@LT.lt.{0} Nat instLTNat i n →
@LE.le.{0} Int Int.instLEInt (@abs.{0} Int instLatticeInt Int.instAddGroup (x i))
(@Nat.cast.{0} Int instNatCastInt U)),
Light.Meets lim P p d
(@List.cons.{0} Int (@Nat.cast.{0} Int instNatCastInt src)
(@List.cons.{0} Int (@Nat.cast.{0} Int instNatCastInt colors)
(@List.cons.{0} Int (@Nat.cast.{0} Int instNatCastInt dst)
(@List.cons.{0} Int (@Nat.cast.{0} Int instNatCastInt n)
(@List.cons.{0} Int (@Nat.cast.{0} Int instNatCastInt want)
(@List.cons.{0} Int scale (@List.nil.{0} Int)))))))
μ (ThreeSum.LightClassFilter.time n) fun (r : Int) (ν : Nat → Int) =>
And
(@Eq.{1} Int r
(@Nat.cast.{0} Int instNatCastInt
(@List.length.{0} Int (ThreeSum.LightClassFilter.items x color want scale n))))
(And
(@Eq.{1} Int (ν dst)
(@Nat.cast.{0} Int instNatCastInt
(@List.length.{0} Int (ThreeSum.LightClassFilter.items x color want scale n))))
(And
(Light.Seg ν
(@HAdd.hAdd.{0, 0, 0} Nat Nat Nat (@instHAdd.{0} Nat instAddNat) dst
(@OfNat.ofNat.{0} Nat (nat_lit 1) (instOfNatNat (nat_lit 1))))
(ThreeSum.LightClassFilter.items x color want scale n))
(Light.SameOutside μ ν dst
(@HAdd.hAdd.{0, 0, 0} Nat Nat Nat (@instHAdd.{0} Nat instAddNat) n
(@OfNat.ofNat.{0} Nat (nat_lit 1) (instOfNatNat (nat_lit 1))))))) := by
sorry
Source