Metamath Proof Explorer


Theorem f1resrcmplf1dlem

Description: Lemma for f1resrcmplf1d . (Contributed by BTernaryTau, 27-Sep-2023)

Ref Expression
Hypotheses f1resrcmplf1dlem.1 φCA
f1resrcmplf1dlem.2 φDA
f1resrcmplf1dlem.3 φF:AB
f1resrcmplf1dlem.4 φFCFD=
Assertion f1resrcmplf1dlem φXCYDFX=FYX=Y

Proof

Step Hyp Ref Expression
1 f1resrcmplf1dlem.1 φCA
2 f1resrcmplf1dlem.2 φDA
3 f1resrcmplf1dlem.3 φF:AB
4 f1resrcmplf1dlem.4 φFCFD=
5 3 ffnd φFFnA
6 fnfvima FFnACAXCFXFC
7 5 6 syl3an1 φCAXCFXFC
8 1 7 syl3an2 φφXCFXFC
9 8 3anidm12 φXCFXFC
10 9 ex φXCFXFC
11 fnfvima FFnADAYDFYFD
12 5 11 syl3an1 φDAYDFYFD
13 2 12 syl3an2 φφYDFYFD
14 13 3anidm12 φYDFYFD
15 14 ex φYDFYFD
16 disjne FCFD=FXFCFYFDFXFY
17 4 16 syl3an1 φFXFCFYFDFXFY
18 17 3expib φFXFCFYFDFXFY
19 neneq FXFY¬FX=FY
20 19 pm2.21d FXFYFX=FYX=Y
21 18 20 syl6 φFXFCFYFDFX=FYX=Y
22 10 15 21 syl2and φXCYDFX=FYX=Y