Theorem nfmov

Bound-variable hypothesis builder for the at-most-one quantifier. See nfmo for a version without disjoint variable conditions but requiring [ax-13]. (Contributed by NM, 9-Mar-1995.) (Revised by Wolf Lammen, 2-Oct-2023.)

Hypothesis
nfmov.1
\( \vdash \Finv x \, \varphi \)
Conclusion
\( \vdash \Finv x \, \exists^\ast y \, \varphi \)
Proof
l0
nftru
nfmov.1
a1i _
nfmodv l0 _
mptru _