English
Any homomorphism F : N ⋊[φ] G →* H is determined by its restrictions to N and G; F = lift (F ∘ inl) (F ∘ inr) h.
Русский
Любое гомоморфизм F: N ⋊[φ] G →* H задаётся своими ограничениями на N и G; F = lift (F ∘ inl) (F ∘ inr) h.
LaTeX
$$$ F = \text{lift} (F \circ inl) (F \circ inr) h $$$
Lean4
theorem lift_unique (F : N ⋊[φ] G →* H) : F = lift (F.comp inl) (F.comp inr) fun _ ↦ by ext; simp [inl_aut] :=
by
rw [DFunLike.ext_iff]
simp only [lift, MonoidHom.comp_apply, MonoidHom.coe_mk, OneHom.coe_mk, ← map_mul, inl_left_mul_inr_right,
forall_const]