Metamath Proof Explorer


Theorem grlimgredgex

Description: Local isomorphisms between simple pseudographs map an edge onto an edge with an endpoint being the image of one of the endpoints of the first edge under the local isomorphism. (Contributed by AV, 28-Dec-2025)

Ref Expression
Hypotheses grlimgredgex.i 𝐼 = ( Edg ‘ 𝐺 )
grlimgredgex.e 𝐸 = ( Edg ‘ 𝐻 )
grlimgredgex.v 𝑉 = ( Vtx ‘ 𝐻 )
grlimgredgex.a ( 𝜑𝐴𝑋 )
grlimgredgex.b ( 𝜑𝐵𝑌 )
grlimgredgex.p ( 𝜑 → { 𝐴 , 𝐵 } ∈ 𝐼 )
grlimgredgex.g ( 𝜑𝐺 ∈ USPGraph )
grlimgredgex.h ( 𝜑𝐻 ∈ USPGraph )
grlimgredgex.f ( 𝜑𝐹 ∈ ( 𝐺 GraphLocIso 𝐻 ) )
Assertion grlimgredgex ( 𝜑 → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 )

Proof

Step Hyp Ref Expression
1 grlimgredgex.i 𝐼 = ( Edg ‘ 𝐺 )
2 grlimgredgex.e 𝐸 = ( Edg ‘ 𝐻 )
3 grlimgredgex.v 𝑉 = ( Vtx ‘ 𝐻 )
4 grlimgredgex.a ( 𝜑𝐴𝑋 )
5 grlimgredgex.b ( 𝜑𝐵𝑌 )
6 grlimgredgex.p ( 𝜑 → { 𝐴 , 𝐵 } ∈ 𝐼 )
7 grlimgredgex.g ( 𝜑𝐺 ∈ USPGraph )
8 grlimgredgex.h ( 𝜑𝐻 ∈ USPGraph )
9 grlimgredgex.f ( 𝜑𝐹 ∈ ( 𝐺 GraphLocIso 𝐻 ) )
10 eqid ( 𝐺 ClNeighbVtx 𝐴 ) = ( 𝐺 ClNeighbVtx 𝐴 )
11 eqid { 𝑥𝐼𝑥 ⊆ ( 𝐺 ClNeighbVtx 𝐴 ) } = { 𝑥𝐼𝑥 ⊆ ( 𝐺 ClNeighbVtx 𝐴 ) }
12 eqid ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) = ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) )
13 eqid { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } = { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) }
14 10 1 11 12 2 13 grlimprclnbgrvtx ( ( ( 𝐺 ∈ USPGraph ∧ 𝐻 ∈ USPGraph ) ∧ 𝐹 ∈ ( 𝐺 GraphLocIso 𝐻 ) ∧ ( 𝐴𝑋𝐵𝑌 ∧ { 𝐴 , 𝐵 } ∈ 𝐼 ) ) → ∃ 𝑓 ( 𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ∧ ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ∨ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) ) )
15 7 8 9 4 5 6 14 syl213anc ( 𝜑 → ∃ 𝑓 ( 𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ∧ ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ∨ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) ) )
16 f1of ( 𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) → 𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) ⟶ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) )
17 16 adantl ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → 𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) ⟶ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) )
18 uspgrupgr ( 𝐺 ∈ USPGraph → 𝐺 ∈ UPGraph )
19 7 18 syl ( 𝜑𝐺 ∈ UPGraph )
20 4 5 jca ( 𝜑 → ( 𝐴𝑋𝐵𝑌 ) )
21 19 20 6 3jca ( 𝜑 → ( 𝐺 ∈ UPGraph ∧ ( 𝐴𝑋𝐵𝑌 ) ∧ { 𝐴 , 𝐵 } ∈ 𝐼 ) )
22 eqid ( Vtx ‘ 𝐺 ) = ( Vtx ‘ 𝐺 )
23 22 1 upgrpredgv ( ( 𝐺 ∈ UPGraph ∧ ( 𝐴𝑋𝐵𝑌 ) ∧ { 𝐴 , 𝐵 } ∈ 𝐼 ) → ( 𝐴 ∈ ( Vtx ‘ 𝐺 ) ∧ 𝐵 ∈ ( Vtx ‘ 𝐺 ) ) )
24 simpr ( ( 𝐴 ∈ ( Vtx ‘ 𝐺 ) ∧ 𝐵 ∈ ( Vtx ‘ 𝐺 ) ) → 𝐵 ∈ ( Vtx ‘ 𝐺 ) )
25 21 23 24 3syl ( 𝜑𝐵 ∈ ( Vtx ‘ 𝐺 ) )
26 simpl ( ( 𝐴 ∈ ( Vtx ‘ 𝐺 ) ∧ 𝐵 ∈ ( Vtx ‘ 𝐺 ) ) → 𝐴 ∈ ( Vtx ‘ 𝐺 ) )
27 21 23 26 3syl ( 𝜑𝐴 ∈ ( Vtx ‘ 𝐺 ) )
28 22 1 predgclnbgrel ( ( 𝐵 ∈ ( Vtx ‘ 𝐺 ) ∧ 𝐴 ∈ ( Vtx ‘ 𝐺 ) ∧ { 𝐴 , 𝐵 } ∈ 𝐼 ) → 𝐵 ∈ ( 𝐺 ClNeighbVtx 𝐴 ) )
29 25 27 6 28 syl3anc ( 𝜑𝐵 ∈ ( 𝐺 ClNeighbVtx 𝐴 ) )
30 29 adantr ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → 𝐵 ∈ ( 𝐺 ClNeighbVtx 𝐴 ) )
31 17 30 ffvelcdmd ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → ( 𝑓𝐵 ) ∈ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) )
32 3 clnbgrisvtx ( ( 𝑓𝐵 ) ∈ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) → ( 𝑓𝐵 ) ∈ 𝑉 )
33 31 32 syl ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → ( 𝑓𝐵 ) ∈ 𝑉 )
34 33 adantr ( ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) → ( 𝑓𝐵 ) ∈ 𝑉 )
35 preq2 ( 𝑣 = ( 𝑓𝐵 ) → { ( 𝐹𝐴 ) , 𝑣 } = { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } )
36 35 eleq1d ( 𝑣 = ( 𝑓𝐵 ) → ( { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ↔ { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ 𝐸 ) )
37 36 adantl ( ( ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) ∧ 𝑣 = ( 𝑓𝐵 ) ) → ( { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ↔ { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ 𝐸 ) )
38 sseq1 ( 𝑥 = { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } → ( 𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ↔ { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) )
39 38 elrab ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ↔ ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ 𝐸 ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) )
40 39 simplbi ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } → { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ 𝐸 )
41 40 adantl ( ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) → { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ 𝐸 )
42 34 37 41 rspcedvd ( ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 )
43 42 ex ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ) )
44 22 clnbgrvtxel ( 𝐴 ∈ ( Vtx ‘ 𝐺 ) → 𝐴 ∈ ( 𝐺 ClNeighbVtx 𝐴 ) )
45 27 44 syl ( 𝜑𝐴 ∈ ( 𝐺 ClNeighbVtx 𝐴 ) )
46 45 adantr ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → 𝐴 ∈ ( 𝐺 ClNeighbVtx 𝐴 ) )
47 17 46 ffvelcdmd ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → ( 𝑓𝐴 ) ∈ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) )
48 3 clnbgrisvtx ( ( 𝑓𝐴 ) ∈ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) → ( 𝑓𝐴 ) ∈ 𝑉 )
49 47 48 syl ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → ( 𝑓𝐴 ) ∈ 𝑉 )
50 49 adantr ( ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) → ( 𝑓𝐴 ) ∈ 𝑉 )
51 preq2 ( 𝑣 = ( 𝑓𝐴 ) → { ( 𝐹𝐴 ) , 𝑣 } = { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } )
52 51 eleq1d ( 𝑣 = ( 𝑓𝐴 ) → ( { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ↔ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ 𝐸 ) )
53 52 adantl ( ( ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) ∧ 𝑣 = ( 𝑓𝐴 ) ) → ( { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ↔ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ 𝐸 ) )
54 sseq1 ( 𝑥 = { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } → ( 𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ↔ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) )
55 54 elrab ( { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ↔ ( { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ 𝐸 ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) )
56 55 simplbi ( { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } → { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ 𝐸 )
57 56 adantl ( ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) → { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ 𝐸 )
58 50 53 57 rspcedvd ( ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) ∧ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 )
59 58 ex ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → ( { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ) )
60 43 59 jaod ( ( 𝜑𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ) → ( ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ∨ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ) )
61 60 expimpd ( 𝜑 → ( ( 𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ∧ ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ∨ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) ) → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ) )
62 61 exlimdv ( 𝜑 → ( ∃ 𝑓 ( 𝑓 : ( 𝐺 ClNeighbVtx 𝐴 ) –1-1-onto→ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) ∧ ( { ( 𝐹𝐴 ) , ( 𝑓𝐵 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ∨ { ( 𝐹𝐴 ) , ( 𝑓𝐴 ) } ∈ { 𝑥𝐸𝑥 ⊆ ( 𝐻 ClNeighbVtx ( 𝐹𝐴 ) ) } ) ) → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 ) )
63 15 62 mpd ( 𝜑 → ∃ 𝑣𝑉 { ( 𝐹𝐴 ) , 𝑣 } ∈ 𝐸 )