Theorem ssrabi

Description: Inference of restricted abstraction subclass from implication. (Contributed by Peter Mazsa, 26-Oct-2022)

	Ref	Expression
Hypothesis	ssrabi.1	|- ( ph -> ps )
Assertion	ssrabi	|- { x e. A | ph } C_ { x e. A | ps }

Proof

Step	Hyp	Ref	Expression
1		ssrabi.1	|- ( ph -> ps )
2	1	a1i	|- ( x e. A -> ( ph -> ps ) )
3	2	ss2rabi	|- { x e. A | ph } C_ { x e. A | ps }