Theorem pm2.24d

Deduction form of pm2.24. (Contributed by NM, 30-Jan-2006.)

Hypothesis
pm2.24d.1
\( \vdash \varphi \rightarrow \psi \)
Conclusion
\( \vdash \varphi \rightarrow \neg \psi \rightarrow \chi \)
Proof
pm2.24d.1
a1d _
con1d _