bi.bldsbd

Theorem.

Arguments:

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

Hypotheses:

(phito(psileftrightarrowchi))
(x bound in phi)

Assertions:

(phito([y/x]psileftrightarrow[y/x]chi))

Proof:

Hyp Ref Line Expr
Hypo1(phito(psileftrightarrowchi))
2(x bound in phi)
1, 2imgen>i3(phitoforallx(psileftrightarrowchi))
bi.bldsbt4(forallx(psileftrightarrowchi)to([y/x]psileftrightarrow[y/x]chi))
3, 4syl5(phito([y/x]psileftrightarrow[y/x]chi))