Metamath Proof Explorer


Theorem pm10.52

Description: Theorem *10.52 in WhiteheadRussell p. 155. (Contributed by Andrew Salmon, 24-May-2011)

Ref Expression
Assertion pm10.52 xφxφψψ

Proof

Step Hyp Ref Expression
1 19.23v xφψxφψ
2 pm5.5 xφxφψψ
3 1 2 syl5bb xφxφψψ