Theorem exp44

An exportation inference. (Contributed by NM, 26-Apr-1994.)

Hypothesis
exp44.1
\( \vdash \varphi \wedge (\psi \wedge \chi \wedge \theta) \rightarrow \tau \)
Conclusion
\( \vdash \varphi \rightarrow \psi \rightarrow \chi \rightarrow \theta \rightarrow \tau \)
Proof
exp44.1
exp32 _
expd _