exor<

Theorem.

Arguments:

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

Hypotheses:

(x bound in phi)

Assertions:

(existsx(phiveepsi)leftrightarrow(phiveeexistsxpsi))

Proof:

Hyp Ref Line Expr
Hypo1(x bound in phi)
ex.ordi2(existsx(phiveepsi)leftrightarrow(existsxphiveeexistsxpsi))
1fv.eqex3(phileftrightarrowexistsxphi)
3bi.bldor<4((phiveeexistsxpsi)leftrightarrow(existsxphiveeexistsxpsi))
2, 4><bitr5(existsx(phiveepsi)leftrightarrow(phiveeexistsxpsi))