Theorem impl

Export a wff from a left conjunct. (Contributed by Mario Carneiro, 9-Jul-2014.)

Hypothesis
impl.1
\( \vdash \varphi \rightarrow \psi \wedge \chi \rightarrow \theta \)
Conclusion
\( \vdash \varphi \wedge \psi \wedge \chi \rightarrow \theta \)
Proof
impl.1
expd _
imp31 _