Theorem pm3.48

Theorem *3.48 of [WhiteheadRussell] p. 114. (Contributed by NM, 28-Jan-1997.)

Conclusion
\( \vdash (\varphi \rightarrow \psi) \wedge (\chi \rightarrow \theta) \rightarrow \varphi \vee \chi \rightarrow \psi \vee \theta \)
Proof
orc
l1
imim2i _
olc
imim2i _
jaao l1 _