Theorem albidv

Formula-building rule for universal quantifier (deduction form). See also albidh and albid. (Contributed by NM, 26-May-1993.)

Hypothesis
albidv.1
\( \vdash \varphi \rightarrow (\psi \leftrightarrow \chi) \)
Conclusion
\( \vdash \varphi \rightarrow (\forall x \, \psi \leftrightarrow \forall x \, \chi) \)
Proof
l0
ax-5
albidv.1
albidh l0 _