Theorem simp1d

Deduce a conjunct from a triple conjunction. (Contributed by NM, 4-Sep-2005.)

Hypothesis
3simp1d.1
\( \vdash \varphi \rightarrow \psi \wedge \chi \wedge \theta \)
Conclusion
\( \vdash \varphi \rightarrow \psi \)
Proof
l0
3simp1d.1
\( \vdash \varphi \rightarrow \psi \wedge \chi \wedge \theta \)
simp1
\( \vdash \psi \wedge \chi \wedge \theta \rightarrow \psi \)
syl l0 _