Metamath Proof Explorer


Theorem simp21l

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

Ref Expression
Assertion simp21l τφψχθηφ

Proof

Step Hyp Ref Expression
1 simp1l φψχθφ
2 1 3ad2ant2 τφψχθηφ