chvar

Theorem.

Arguments:

x (sv), y (sv), phi (pr), psi (pr),

Hypotheses:

phi
((xeqy)to(phileftrightarrowpsi))
(x bound in psi)

Assertions:

psi

Proof:

Hyp Ref Line Expr
Hypo1phi
2((xeqy)to(phileftrightarrowpsi))
3(x bound in psi)
2bi>4((xeqy)to(phitopsi))
3, 4ax4a5(forallxphitopsi)
1, 5mpg6psi