Theorem nfrmowOLD

Description: Obsolete version of nfrmow as of 21-Nov-2024. (Contributed by NM, 16-Jun-2017) (Revised by Gino Giotto, 10-Jan-2024) (Proof modification is discouraged.) (New usage is discouraged.)

	Ref	Expression
Hypotheses	nfreuw.1	$$⊢\underset{\_}{Ⅎ}xA$$
	nfreuw.2	$$⊢Ⅎx\phi$$
Assertion	nfrmowOLD	$$⊢Ⅎx{\exists }^{*}y\in A\phi$$

Proof

Step	Hyp	Ref	Expression
1		nfreuw.1	$$⊢\underset{\_}{Ⅎ}xA$$
2		nfreuw.2	$$⊢Ⅎx\phi$$
3		df-rmo	$$⊢{\exists }^{*}y\in A\phi \leftrightarrow {\exists }^{*}y\left(y\in A\wedge \phi \right)$$
4		nftru	$$⊢Ⅎy\top$$
5		nfcvd	$$⊢\top \to \underset{\_}{Ⅎ}xy$$
6	1	a1i	$$⊢\top \to \underset{\_}{Ⅎ}xA$$
7	5 6	nfeld	$$⊢\top \to Ⅎxy\in A$$
8	2	a1i	$$⊢\top \to Ⅎx\phi$$
9	7 8	nfand	$$⊢\top \to Ⅎx\left(y\in A\wedge \phi \right)$$
10	4 9	nfmodv	$$⊢\top \to Ⅎx{\exists }^{*}y\left(y\in A\wedge \phi \right)$$
11	10	mptru	$$⊢Ⅎx{\exists }^{*}y\left(y\in A\wedge \phi \right)$$
12	3 11	nfxfr	$$⊢Ⅎx{\exists }^{*}y\in A\phi$$