Theorem expd

Exportation deduction. (Contributed by NM, 20-Aug-1993.) (Proof shortened by Wolf Lammen, 28-Jul-2022.)

Hypothesis
expd.1
\( \vdash \varphi \rightarrow \psi \wedge \chi \rightarrow \theta \)
Conclusion
\( \vdash \varphi \rightarrow \psi \rightarrow \chi \rightarrow \theta \)
Proof
expd.1
expdcom _
com3r _