Metamath Proof Explorer


Theorem cmnmnd

Description: A commutative monoid is a monoid. (Contributed by Mario Carneiro, 6-Jan-2015)

Ref Expression
Assertion cmnmnd ⊢ G ∈ CMnd → G ∈ Mnd

Proof

Step Hyp Ref Expression
1 eqid ⊢ Base G = Base G
2 eqid ⊢ + G = + G
3 1 2 iscmn ⊢ G ∈ CMnd ↔ G ∈ Mnd ∧ ∀ x ∈ Base G ∀ y ∈ Base G x + G y = y + G x
4 3 simplbi ⊢ G ∈ CMnd → G ∈ Mnd