Metamath Proof Explorer


Theorem uspgredg2vlem

Description: Lemma for uspgredg2v . (Contributed by Alexander van der Vekens, 4-Jan-2018) (Revised by AV, 6-Dec-2020)

Ref Expression
Hypotheses uspgredg2v.v V=VtxG
uspgredg2v.e E=EdgG
uspgredg2v.a A=eE|Ne
Assertion uspgredg2vlem GUSHGraphYAιzV|Y=NzV

Proof

Step Hyp Ref Expression
1 uspgredg2v.v V=VtxG
2 uspgredg2v.e E=EdgG
3 uspgredg2v.a A=eE|Ne
4 eleq2 e=YNeNY
5 4 3 elrab2 YAYENY
6 simpl GUSHGraphYENYGUSHGraph
7 2 eleq2i YEYEdgG
8 7 biimpi YEYEdgG
9 8 ad2antrl GUSHGraphYENYYEdgG
10 simprr GUSHGraphYENYNY
11 6 9 10 3jca GUSHGraphYENYGUSHGraphYEdgGNY
12 uspgredg2vtxeu GUSHGraphYEdgGNY∃!zVtxGY=Nz
13 reueq1 V=VtxG∃!zVY=Nz∃!zVtxGY=Nz
14 1 13 ax-mp ∃!zVY=Nz∃!zVtxGY=Nz
15 12 14 sylibr GUSHGraphYEdgGNY∃!zVY=Nz
16 riotacl ∃!zVY=NzιzV|Y=NzV
17 11 15 16 3syl GUSHGraphYENYιzV|Y=NzV
18 5 17 sylan2b GUSHGraphYAιzV|Y=NzV