Theorem
pm2.47
Theorem *2.47 of [WhiteheadRussell] p. 107. (Contributed by NM, 3-Jan-2005.)
Conclusion
\( \vdash \neg (\varphi \vee \psi) \rightarrow \neg \varphi \vee \psi \)
Proof
pm2.45
orcd
_
This is the content in the right pane.