PhysLean/HepLean/Tensors/Tree/NodeIdentities/ProdComm.lean
2024-10-21 07:17:03 +00:00

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/-
Copyright (c) 2024 Joseph Tooby-Smith. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Authors: Joseph Tooby-Smith
-/
import HepLean.Tensors.Tree.Basic
/-!
# Commuting products
The results here follow from the properties of Monoidal categories and monoidal functors.
-/
open IndexNotation
open CategoryTheory
open MonoidalCategory
open OverColor
open HepLean.Fin
namespace TensorTree
variable {S : TensorStruct} {n n2 : }
(c : Fin n → S.C) (c2 : Fin n2 → S.C)
def braidPerm : OverColor.mk (Sum.elim c2 c ∘ ⇑finSumFinEquiv.symm) ⟶
OverColor.mk (Sum.elim c c2 ∘ ⇑finSumFinEquiv.symm) :=
(equivToIso finSumFinEquiv).inv ≫
(BraidedCategory.braiding (OverColor.mk c2) (OverColor.mk c)).hom
≫ (equivToIso finSumFinEquiv).hom
theorem prod_comm (t : TensorTree S c) (t2 : TensorTree S c2) :
(prod t t2).tensor = (perm (braidPerm c c2) (prod t2 t)).tensor := by
sorry
end TensorTree