Metamath Proof Explorer


Theorem bnj1235

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

Ref Expression
Hypothesis bnj1235.1 φψχθτ
Assertion bnj1235 φχ

Proof

Step Hyp Ref Expression
1 bnj1235.1 φψχθτ
2 id χχ
3 1 2 bnj770 φχ