Theorem dmeqi

Description: Equality inference for domain. (Contributed by NM, 4-Mar-2004)

	Ref	Expression
Hypothesis	dmeqi.1	|- A = B
Assertion	dmeqi	|- dom A = dom B

Proof

Step	Hyp	Ref	Expression
1		dmeqi.1	|- A = B
2		dmeq	|- ( A = B -> dom A = dom B )
3	1 2	ax-mp	|- dom A = dom B