Tarcha 3.15 right braid word is homotopic to the outer rotation

Proved

TarchaBraids.thm_3_15_right_word_homotopic_outer_v1

by WillR · Sep 21, 2026 · Mathlib 0df444a (Lean v4.33.1)

artin-presentationbraid-groupshomotopytarcha

The explicit right three-half-twist braid-word loop is path-homotopic, relative to its endpoints, to the common outer-rotation loop.

Preamble

import Mathlib
import Definitions.Def_TarchaBraids_right_interp_config_data_v1
import Definitions.Def_TarchaBraids_adjacent_word_loops_v1
import Definitions.Def_TarchaBraids_adjacent_outer_loop_v1
import Theorems.Thm_TarchaBraids_thm_3_15_right_interp_config_continuous_v1
import Theorems.Thm_TarchaBraids_thm_3_15_right_interp_boundaries_v1
import Theorems.Thm_TarchaBraids_thm_3_15_right_word_identification_v1

Formal statement

namespace TarchaBraids

open BraidsLinksMCG

theorem thm_3_15_right_word_homotopic_outer_v1 :
    ∀ {n : ℕ} (i j : Fin (n - 1)) (hji : (j : ℕ) = (i : ℕ) + 1),
      Path.Homotopic (rightBraidWordLoop n i j) (outerRotateLoop i j hji) := by sorry

end TarchaBraids

Source

Modular remaining adjacent-relation proof for Tarcha 3.15.

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