Mathlib Map

Theorems · Theorem · group theory

Submonoid.exists_mulEquiv_eq_mgraph

∀ {H : Type u_2} {I : Type u_3} [inst : Monoid H] [inst_1 : Monoid I] {G : Submonoid (H × I)},
  Function.Bijective (Prod.fst ∘ ⇑G.subtype) →
    Function.Bijective (Prod.snd ∘ ⇑G.subtype) → ∃ e, G = e.toMonoidHom.mgraph

Goursat's lemma for monoid isomorphisms. Let G ≤ H × I be a submonoid of a product of monoids. Assume that the natural maps from G to both factors are bijective. Then G is the graph of some isomorphism f : H ≃* I.

Defined in
Mathlib.Algebra.Group.Graph
Cited by
1 results in Mathlib
Foundations
Depth 23 from the axioms · uses propext, Classical.choice, Quot.sound
Assumes
MonoidMonoid

Around this declaration

Dashed lines are statement dependencies; solid lines are citations in proofs.

Cites14

Mathlib declarations this one mentions in its statement or cites explicitly in its proof. Plumbing is filtered out.

Cited by1

Results whose statement or proof uses this declaration.