Theorem ofeq

Description: Equality theorem for function operation. (Contributed by Mario Carneiro, 20-Jul-2014)

	Ref	Expression
Assertion	ofeq	$$⊢R=S\to {\circ }_{f}R={\circ }_{f}S$$

Proof

Step	Hyp	Ref	Expression
1		id	$$⊢R=S\to R=S$$
2	1	ofeqd	$$⊢R=S\to {\circ }_{f}R={\circ }_{f}S$$