Theorem nfae

All variables are effectively bound in an identical variable specifier. Usage of this theorem is discouraged because it depends on [ax-13]. (Contributed by Mario Carneiro, 11-Aug-2016.) (New usage is discouraged.)

Conclusion
\( \vdash \Finv z \, \forall x \, x = y \)
Proof
hbae
nf5i _