Theorem 3albii

Inference adding three universal quantifiers to both sides of an equivalence. (Contributed by Peter Mazsa, 10-Aug-2018.)

Hypothesis
albii.1
\( \vdash \varphi \leftrightarrow \psi \)
Conclusion
\( \vdash \forall x \, \forall y \, \forall z \, \varphi \leftrightarrow \forall x \, \forall y \, \forall z \, \psi \)
Proof
albii.1
2albii _
albii _