Database
ZF (ZERMELO-FRAENKEL) SET THEORY
ZF Set Theory - start with the Axiom of Extensionality
Restricted quantification
nfrmow
Metamath Proof Explorer
Description: Bound-variable hypothesis builder for restricted uniqueness. Version of
nfrmo with a disjoint variable condition, which does not require
ax-13 . (Contributed by NM , 16-Jun-2017) (Revised by Gino Giotto , 10-Jan-2024)
Ref
Expression
Hypotheses
nfreuw.1
|- F/_ x A
nfreuw.2
|- F/ x ph
Assertion
nfrmow
|- F/ x E* y e. A ph
Proof
Step
Hyp
Ref
Expression
1
nfreuw.1
|- F/_ x A
2
nfreuw.2
|- F/ x ph
3
df-rmo
|- ( E* y e. A ph <-> E* y ( y e. A /\ ph ) )
4
nftru
|- F/ y T.
5
nfcvd
|- ( T. -> F/_ x y )
6
1
a1i
|- ( T. -> F/_ x A )
7
5 6
nfeld
|- ( T. -> F/ x y e. A )
8
2
a1i
|- ( T. -> F/ x ph )
9
7 8
nfand
|- ( T. -> F/ x ( y e. A /\ ph ) )
10
4 9
nfmodv
|- ( T. -> F/ x E* y ( y e. A /\ ph ) )
11
10
mptru
|- F/ x E* y ( y e. A /\ ph )
12
3 11
nfxfr
|- F/ x E* y e. A ph