Metamath Proof Explorer


Theorem i1fposd

Description: Deduction form of i1fposd . (Contributed by Mario Carneiro, 6-Aug-2014)

Ref Expression
Hypothesis i1fposd.1 φxAdom1
Assertion i1fposd φxif0AA0dom1

Proof

Step Hyp Ref Expression
1 i1fposd.1 φxAdom1
2 nfcv _x0
3 nfcv _x
4 nffvmpt1 _xxAy
5 2 3 4 nfbr x0xAy
6 5 4 2 nfif _xif0xAyxAy0
7 nfcv _yif0xAxxAx0
8 fveq2 y=xxAy=xAx
9 8 breq2d y=x0xAy0xAx
10 9 8 ifbieq1d y=xif0xAyxAy0=if0xAxxAx0
11 6 7 10 cbvmpt yif0xAyxAy0=xif0xAxxAx0
12 simpr φxx
13 i1ff xAdom1xA:
14 1 13 syl φxA:
15 14 fvmptelcdm φxA
16 eqid xA=xA
17 16 fvmpt2 xAxAx=A
18 12 15 17 syl2anc φxxAx=A
19 18 breq2d φx0xAx0A
20 19 18 ifbieq1d φxif0xAxxAx0=if0AA0
21 20 mpteq2dva φxif0xAxxAx0=xif0AA0
22 11 21 eqtrid φyif0xAyxAy0=xif0AA0
23 eqid yif0xAyxAy0=yif0xAyxAy0
24 23 i1fpos xAdom1yif0xAyxAy0dom1
25 1 24 syl φyif0xAyxAy0dom1
26 22 25 eqeltrrd φxif0AA0dom1