Theorem pm2.86i

Inference associated with pm2.86. (Contributed by NM, 5-Aug-1993.) (Proof shortened by Wolf Lammen, 3-Apr-2013.)

Hypothesis
pm2.86i.1
\( \vdash (\varphi \rightarrow \psi) \rightarrow \varphi \rightarrow \chi \)
Conclusion
\( \vdash \varphi \rightarrow \psi \rightarrow \chi \)
Proof
pm2.86i.1
\( \vdash (\varphi \rightarrow \psi) \rightarrow \varphi \rightarrow \chi \)
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