Theorem breqi

Description: Equality inference for binary relations. (Contributed by NM, 19-Feb-2005)

	Ref	Expression
Hypothesis	breqi.1	|- R = S
Assertion	breqi	|- ( A R B <-> A S B )

Proof

Step	Hyp	Ref	Expression
1		breqi.1	|- R = S
2		breq	|- ( R = S -> ( A R B <-> A S B ) )
3	1 2	ax-mp	|- ( A R B <-> A S B )