Tarcha adjacent common outer-rotation loop
DefinitionTarchaBraids_adjacent_outer_loop_v1artin-presentationbraid-groupshomotopytarcha
The common outer-rotation loop used as the comparison path for the two adjacent three-half-twist words.
Definition code
import Mathlib
import Definitions.Def_TarchaBraids_adjacent_config_data_v1
import Theorems.Thm_TarchaBraids_thm_3_15_adjacent_config_continuous_v1
import Theorems.Thm_TarchaBraids_thm_3_15_adjacent_raw_zero_endpoints_v1
import Theorems.Thm_TarchaBraids_thm_3_15_adjacent_outer_one_endpoint_v1
namespace TarchaBraids
noncomputable section
open BraidsLinksMCG
def outerRotateLoop {n : ℕ} (i j : Fin (n - 1))
(hji : (j : ℕ) = (i : ℕ) + 1) : Path (baseUnordered n) (baseUnordered n) := by
have hi2 : (i : ℕ) + 2 < n := by
have hj := j.isLt
omega
exact
{ toFun := fun q => configProj n (outerRotateConfig i hi2 (q : ℝ))
continuous_toFun :=
(configProj n).continuous.comp
((thm_3_15_adjacent_config_continuous_v1.2.2 i hi2).comp continuous_subtype_val)
source' := by
change configProj n (outerRotateConfig i hi2 0) = configProj n (baseOrdered n)
apply congrArg (configProj n)
apply Subtype.ext
exact thm_3_15_adjacent_raw_zero_endpoints_v1.2.2 n i
target' := by
change configProj n (outerRotateConfig i hi2 1) = configProj n (baseOrdered n)
have hfun := thm_3_15_adjacent_outer_one_endpoint_v1 i j hji hi2
have h : configProj n (baseOrdered n) =
configProj n (outerRotateConfig i hi2 1) := by
apply Quotient.sound
refine ⟨Equiv.swap (strandIdx i) (strandIdxSucc j), ?_⟩
exact hfun
exact h.symm }
end
end TarchaBraids
Source
Modular common-loop layer extracted from Tarcha's adjacent Artin relation proof.