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Mirrors > Home > MPE Home > Th. List > dfnbgr3 | Structured version Visualization version GIF version |
Description: Alternate definition of the neighbors of a vertex using the edge function instead of the edges themselves (see also nbgrval 27112). (Contributed by Alexander van der Vekens, 17-Dec-2017.) (Revised by AV, 25-Oct-2020.) (Revised by AV, 21-Mar-2021.) |
Ref | Expression |
---|---|
dfnbgr3.v | ⊢ 𝑉 = (Vtx‘𝐺) |
dfnbgr3.i | ⊢ 𝐼 = (iEdg‘𝐺) |
Ref | Expression |
---|---|
dfnbgr3 | ⊢ ((𝑁 ∈ 𝑉 ∧ Fun 𝐼) → (𝐺 NeighbVtx 𝑁) = {𝑛 ∈ (𝑉 ∖ {𝑁}) ∣ ∃𝑖 ∈ dom 𝐼{𝑁, 𝑛} ⊆ (𝐼‘𝑖)}) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | dfnbgr3.v | . . . 4 ⊢ 𝑉 = (Vtx‘𝐺) | |
2 | eqid 2821 | . . . 4 ⊢ (Edg‘𝐺) = (Edg‘𝐺) | |
3 | 1, 2 | nbgrval 27112 | . . 3 ⊢ (𝑁 ∈ 𝑉 → (𝐺 NeighbVtx 𝑁) = {𝑛 ∈ (𝑉 ∖ {𝑁}) ∣ ∃𝑒 ∈ (Edg‘𝐺){𝑁, 𝑛} ⊆ 𝑒}) |
4 | 3 | adantr 483 | . 2 ⊢ ((𝑁 ∈ 𝑉 ∧ Fun 𝐼) → (𝐺 NeighbVtx 𝑁) = {𝑛 ∈ (𝑉 ∖ {𝑁}) ∣ ∃𝑒 ∈ (Edg‘𝐺){𝑁, 𝑛} ⊆ 𝑒}) |
5 | edgval 26828 | . . . . . 6 ⊢ (Edg‘𝐺) = ran (iEdg‘𝐺) | |
6 | dfnbgr3.i | . . . . . . . 8 ⊢ 𝐼 = (iEdg‘𝐺) | |
7 | 6 | eqcomi 2830 | . . . . . . 7 ⊢ (iEdg‘𝐺) = 𝐼 |
8 | 7 | rneqi 5801 | . . . . . 6 ⊢ ran (iEdg‘𝐺) = ran 𝐼 |
9 | 5, 8 | eqtri 2844 | . . . . 5 ⊢ (Edg‘𝐺) = ran 𝐼 |
10 | 9 | rexeqi 3414 | . . . 4 ⊢ (∃𝑒 ∈ (Edg‘𝐺){𝑁, 𝑛} ⊆ 𝑒 ↔ ∃𝑒 ∈ ran 𝐼{𝑁, 𝑛} ⊆ 𝑒) |
11 | funfn 6379 | . . . . . . 7 ⊢ (Fun 𝐼 ↔ 𝐼 Fn dom 𝐼) | |
12 | 11 | biimpi 218 | . . . . . 6 ⊢ (Fun 𝐼 → 𝐼 Fn dom 𝐼) |
13 | 12 | adantl 484 | . . . . 5 ⊢ ((𝑁 ∈ 𝑉 ∧ Fun 𝐼) → 𝐼 Fn dom 𝐼) |
14 | sseq2 3992 | . . . . . 6 ⊢ (𝑒 = (𝐼‘𝑖) → ({𝑁, 𝑛} ⊆ 𝑒 ↔ {𝑁, 𝑛} ⊆ (𝐼‘𝑖))) | |
15 | 14 | rexrn 6847 | . . . . 5 ⊢ (𝐼 Fn dom 𝐼 → (∃𝑒 ∈ ran 𝐼{𝑁, 𝑛} ⊆ 𝑒 ↔ ∃𝑖 ∈ dom 𝐼{𝑁, 𝑛} ⊆ (𝐼‘𝑖))) |
16 | 13, 15 | syl 17 | . . . 4 ⊢ ((𝑁 ∈ 𝑉 ∧ Fun 𝐼) → (∃𝑒 ∈ ran 𝐼{𝑁, 𝑛} ⊆ 𝑒 ↔ ∃𝑖 ∈ dom 𝐼{𝑁, 𝑛} ⊆ (𝐼‘𝑖))) |
17 | 10, 16 | syl5bb 285 | . . 3 ⊢ ((𝑁 ∈ 𝑉 ∧ Fun 𝐼) → (∃𝑒 ∈ (Edg‘𝐺){𝑁, 𝑛} ⊆ 𝑒 ↔ ∃𝑖 ∈ dom 𝐼{𝑁, 𝑛} ⊆ (𝐼‘𝑖))) |
18 | 17 | rabbidv 3480 | . 2 ⊢ ((𝑁 ∈ 𝑉 ∧ Fun 𝐼) → {𝑛 ∈ (𝑉 ∖ {𝑁}) ∣ ∃𝑒 ∈ (Edg‘𝐺){𝑁, 𝑛} ⊆ 𝑒} = {𝑛 ∈ (𝑉 ∖ {𝑁}) ∣ ∃𝑖 ∈ dom 𝐼{𝑁, 𝑛} ⊆ (𝐼‘𝑖)}) |
19 | 4, 18 | eqtrd 2856 | 1 ⊢ ((𝑁 ∈ 𝑉 ∧ Fun 𝐼) → (𝐺 NeighbVtx 𝑁) = {𝑛 ∈ (𝑉 ∖ {𝑁}) ∣ ∃𝑖 ∈ dom 𝐼{𝑁, 𝑛} ⊆ (𝐼‘𝑖)}) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 208 ∧ wa 398 = wceq 1533 ∈ wcel 2110 ∃wrex 3139 {crab 3142 ∖ cdif 3932 ⊆ wss 3935 {csn 4560 {cpr 4562 dom cdm 5549 ran crn 5550 Fun wfun 6343 Fn wfn 6344 ‘cfv 6349 (class class class)co 7150 Vtxcvtx 26775 iEdgciedg 26776 Edgcedg 26826 NeighbVtx cnbgr 27108 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1792 ax-4 1806 ax-5 1907 ax-6 1966 ax-7 2011 ax-8 2112 ax-9 2120 ax-10 2141 ax-11 2157 ax-12 2173 ax-ext 2793 ax-sep 5195 ax-nul 5202 ax-pow 5258 ax-pr 5321 ax-un 7455 |
This theorem depends on definitions: df-bi 209 df-an 399 df-or 844 df-3an 1085 df-tru 1536 df-ex 1777 df-nf 1781 df-sb 2066 df-mo 2618 df-eu 2650 df-clab 2800 df-cleq 2814 df-clel 2893 df-nfc 2963 df-ral 3143 df-rex 3144 df-rab 3147 df-v 3496 df-sbc 3772 df-dif 3938 df-un 3940 df-in 3942 df-ss 3951 df-nul 4291 df-if 4467 df-sn 4561 df-pr 4563 df-op 4567 df-uni 4832 df-br 5059 df-opab 5121 df-mpt 5139 df-id 5454 df-xp 5555 df-rel 5556 df-cnv 5557 df-co 5558 df-dm 5559 df-rn 5560 df-iota 6308 df-fun 6351 df-fn 6352 df-fv 6357 df-ov 7153 df-oprab 7154 df-mpo 7155 df-edg 26827 df-nbgr 27109 |
This theorem is referenced by: (None) |
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