Theorem 19.23bi

Inference form of Theorem 19.23 of [Margaris] p. 90, see 19.23. (Contributed by NM, 12-Mar-1993.)

Hypothesis
19.23bi.1
\( \vdash \exists x \, \varphi \rightarrow \psi \)
Conclusion
\( \vdash \varphi \rightarrow \psi \)
Proof
l0
19.8a
\( \vdash \varphi \rightarrow \exists x \, \varphi \)
19.23bi.1
\( \vdash \exists x \, \varphi \rightarrow \psi \)
syl l0 _