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 ( 𝜑 ↔ ( 𝜓𝜒𝜃𝜏 ) )
Assertion bnj1235 ( 𝜑𝜒 )

Proof

Step Hyp Ref Expression
1 bnj1235.1 ( 𝜑 ↔ ( 𝜓𝜒𝜃𝜏 ) )
2 id ( 𝜒𝜒 )
3 1 2 bnj770 ( 𝜑𝜒 )