English
Define a congruence between semidirect products with φ₁, φ₂ given by isomorphisms fn and fg under h.
Русский
Определить конгруэнцию между полупрямыми произведениями с φ₁, φ₂, заданными изоморфизмами fn и fg по h.
LaTeX
$$$ congr : N_1⋊[φ_1]G_1 ≃* N_2⋊[φ_2] G_2 $$$
Lean4
/-- Define a isomorphism from `N₁ ⋊[φ₁] G₁` to `N₂ ⋊[φ₂] G₂` without specifying `φ₂`. -/
@[simps!]
def congr' : N₁ ⋊[φ₁] G₁ ≃* N₂ ⋊[MonoidHom.comp (MulAut.congr fn) (φ₁.comp fg.symm)] G₂ :=
congr fn fg (fun _ ↦ by ext; simp)