Metamath Proof Explorer


Theorem abanssr

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

Ref Expression
Assertion abanssr f | φ ψ f | ψ

Proof

Step Hyp Ref Expression
1 simpr φ ψ ψ
2 1 ss2abi f | φ ψ f | ψ