bvdef

Theorem.

Arguments:

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

Hypotheses:

(phileftrightarrowpsi)
(x bound in psi)

Assertions:

(x bound in phi)

Proof:

Hyp Ref Line Expr
Hypo1(phileftrightarrowpsi)
2(x bound in psi)
2df-Bvp3(psitoforallxpsi)
1eqt-∀-i4(forallxphileftrightarrowforallxpsi)
1, 3, 4<imtr5(phitoforallxphi)
5df-Bvp6(x bound in phi)