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