Theorem mulcomnni

Description: Commutative law for multiplication. (Contributed by metakunt, 25-Apr-2024)

	Ref	Expression
Hypotheses	mulcomnni.1	|- A e. NN
	mulcomnni.2	|- B e. NN
Assertion	mulcomnni	|- ( A x. B ) = ( B x. A )

Proof

Step	Hyp	Ref	Expression
1		mulcomnni.1	|- A e. NN
2		mulcomnni.2	|- B e. NN
3	1	nncni	|- A e. CC
4	2	nncni	|- B e. CC
5	3 4	mulcomi	|- ( A x. B ) = ( B x. A )