English
The composition of prodCongrLeft with prodComm equals the composition of prodComm with prodCongrRight: (prodCongrLeft e).trans (prodComm β₂ α₁) = (prodComm β₁ α₁).trans (prodCongrRight e).
Русский
Слияние prodCongrLeft с prodComm эквивалентно слиянию prodComm с prodCongrRight: (prodCongrLeft e).trans (prodComm β₂ α₁) = (prodComm β₁ α₁).trans (prodCongrRight e).
LaTeX
$$$(prodCongrLeft e).trans (prodComm \beta_2 \alpha_1) = (prodComm \beta_1 \alpha_1).trans (prodCongrRight e)$$$
Lean4
@[simp]
theorem prodCongrLeft_trans_prodComm :
(prodCongrLeft e).trans (prodComm _ _) = (prodComm _ _).trans (prodCongrRight e) :=
by
ext ⟨a, b⟩ : 1
simp