spec

Theorem.

Arguments:

a (st), x (sv), phi (pr),

Dummy variables:

z (sv),

Distinct variable conditions:

(z, a), (z, x), (z, phi),

Assertions:

(forallxphito[a/x]phi)

Proof:

Hyp Ref Line Expr
spec-w1(forallxphito[z/x]phi)
1imgen>i2(forallxphitoforallz[z/x]phi)
spec-w3(forallz[z/x]phito[a/z][z/x]phi)
sbco2w4([a/z][z/x]phito[a/x]phi)
2, 3, 43syl5(forallxphito[a/x]phi)