Theorem abanssl

Description: A class abstraction with a conjunction is a subset of the class abstraction with the left conjunct only. (Contributed by AV, 7-Aug-2024) (Proof shortened by SN, 22-Aug-2024)

	Ref	Expression
Assertion	abanssl	|- { f | ( ph /\ ps ) } C_ { f | ph }

Proof

Step	Hyp	Ref	Expression
1		simpl	|- ( ( ph /\ ps ) -> ph )
2	1	ss2abi	|- { f | ( ph /\ ps ) } C_ { f | ph }