English
From a unique-mul statement in opposite multiplication, deduce a unique-mul statement in the original multiplication.
Русский
Из уникальности разложения в противоположной группе выводим уникальность в исходной группе.
LaTeX
$$UniqueMul (B.map ⟨_, op_injective⟩) (A.map ⟨_, op_injective⟩) (op b0) (op a0) → UniqueMul A B a0 b0$$
Lean4
@[to_additive]
theorem of_mulOpposite (h : UniqueMul (B.map ⟨_, op_injective⟩) (A.map ⟨_, op_injective⟩) (op b0) (op a0)) :
UniqueMul A B a0 b0 := fun a b aA bB ab ↦ by
simpa [and_comm] using h (mem_map_of_mem _ bB) (mem_map_of_mem _ aA) (congr_arg op ab)