Theorem pm3.44

Theorem *3.44 of [WhiteheadRussell] p. 113. (Contributed by NM, 3-Jan-2005.) (Proof shortened by Wolf Lammen, 3-Oct-2013.)

Conclusion
\( \vdash (\psi \rightarrow \varphi) \wedge (\chi \rightarrow \varphi) \rightarrow \psi \vee \chi \rightarrow \varphi \)
Proof
l0
id
id
jaao l0 _