Metamath Proof Explorer


Theorem simp121

Description: Simplification of conjunction. (Contributed by NM, 9-Mar-2012)

Ref Expression
Assertion simp121 θφψχτηζφ

Proof

Step Hyp Ref Expression
1 simp21 θφψχτφ
2 1 3ad2ant1 θφψχτηζφ