Metamath Proof Explorer


Theorem bnj1265

Description: First-order logic and set theory. (Contributed by Jonathan Ben-Naim, 3-Jun-2011) (New usage is discouraged.)

Ref Expression
Hypothesis bnj1265.1 φxAψ
Assertion bnj1265 φψ

Proof

Step Hyp Ref Expression
1 bnj1265.1 φxAψ
2 1 bnj1196 φxxAψ
3 2 bnj1266 φxψ
4 3 bnj937 φψ