Theorem upgrres 27096

Description: A subgraph obtained by removing one vertex and all edges incident with this vertex from a pseudograph (see uhgrspan1 27093) is a pseudograph. (Contributed by AV, 8-Nov-2020.) (Revised by AV, 19-Dec-2021.)

Hypotheses

Ref	Expression
upgrres.v	⊢ 𝑉 = (Vtx‘𝐺)
upgrres.e	⊢ 𝐸 = (iEdg‘𝐺)
upgrres.f	⊢ 𝐹 = {𝑖 ∈ dom 𝐸 ∣ 𝑁 ∉ (𝐸‘𝑖)}
upgrres.s	⊢ 𝑆 = ⟨(𝑉 ∖ {𝑁}), (𝐸 ↾ 𝐹)⟩

Assertion

Ref	Expression
upgrres	⊢ ((𝐺 ∈ UPGraph ∧ 𝑁 ∈ 𝑉) → 𝑆 ∈ UPGraph)

Distinct variable groups:   𝑖,𝐸   𝑖,𝑁

Allowed substitution hints:   𝑆(𝑖)   𝐹(𝑖)   𝐺(𝑖)   𝑉(𝑖)

Proof of Theorem upgrres

Dummy variable 𝑝 is distinct from all other variables.

Step	Hyp	Ref	Expression
1		upgruhgr 26895	. . . . . 6 ⊢ (𝐺 ∈ UPGraph → 𝐺 ∈ UHGraph)
2		upgrres.e	. . . . . . 7 ⊢ 𝐸 = (iEdg‘𝐺)
3	2	uhgrfun 26859	. . . . . 6 ⊢ (𝐺 ∈ UHGraph → Fun 𝐸)
4		funres 6366	. . . . . 6 ⊢ (Fun 𝐸 → Fun (𝐸 ↾ 𝐹))
5	1, 3, 4	3syl 18	. . . . 5 ⊢ (𝐺 ∈ UPGraph → Fun (𝐸 ↾ 𝐹))
6	5	funfnd 6355	. . . 4 ⊢ (𝐺 ∈ UPGraph → (𝐸 ↾ 𝐹) Fn dom (𝐸 ↾ 𝐹))
7	6	adantr 484	. . 3 ⊢ ((𝐺 ∈ UPGraph ∧ 𝑁 ∈ 𝑉) → (𝐸 ↾ 𝐹) Fn dom (𝐸 ↾ 𝐹))
8		upgrres.v	. . . 4 ⊢ 𝑉 = (Vtx‘𝐺)
9		upgrres.f	. . . 4 ⊢ 𝐹 = {𝑖 ∈ dom 𝐸 ∣ 𝑁 ∉ (𝐸‘𝑖)}
10	8, 2, 9	upgrreslem 27094	. . 3 ⊢ ((𝐺 ∈ UPGraph ∧ 𝑁 ∈ 𝑉) → ran (𝐸 ↾ 𝐹) ⊆ {𝑝 ∈ (𝒫 (𝑉 ∖ {𝑁}) ∖ {∅}) ∣ (♯‘𝑝) ≤ 2})
11		df-f 6328	. . 3 ⊢ ((𝐸 ↾ 𝐹):dom (𝐸 ↾ 𝐹)⟶{𝑝 ∈ (𝒫 (𝑉 ∖ {𝑁}) ∖ {∅}) ∣ (♯‘𝑝) ≤ 2} ↔ ((𝐸 ↾ 𝐹) Fn dom (𝐸 ↾ 𝐹) ∧ ran (𝐸 ↾ 𝐹) ⊆ {𝑝 ∈ (𝒫 (𝑉 ∖ {𝑁}) ∖ {∅}) ∣ (♯‘𝑝) ≤ 2}))
12	7, 10, 11	sylanbrc 586	. 2 ⊢ ((𝐺 ∈ UPGraph ∧ 𝑁 ∈ 𝑉) → (𝐸 ↾ 𝐹):dom (𝐸 ↾ 𝐹)⟶{𝑝 ∈ (𝒫 (𝑉 ∖ {𝑁}) ∖ {∅}) ∣ (♯‘𝑝) ≤ 2})
13		upgrres.s	. . . 4 ⊢ 𝑆 = ⟨(𝑉 ∖ {𝑁}), (𝐸 ↾ 𝐹)⟩
14		opex 5321	. . . 4 ⊢ ⟨(𝑉 ∖ {𝑁}), (𝐸 ↾ 𝐹)⟩ ∈ V
15	13, 14	eqeltri 2886	. . 3 ⊢ 𝑆 ∈ V
16	8, 2, 9, 13	uhgrspan1lem2 27091	. . . . 5 ⊢ (Vtx‘𝑆) = (𝑉 ∖ {𝑁})
17	16	eqcomi 2807	. . . 4 ⊢ (𝑉 ∖ {𝑁}) = (Vtx‘𝑆)
18	8, 2, 9, 13	uhgrspan1lem3 27092	. . . . 5 ⊢ (iEdg‘𝑆) = (𝐸 ↾ 𝐹)
19	18	eqcomi 2807	. . . 4 ⊢ (𝐸 ↾ 𝐹) = (iEdg‘𝑆)
20	17, 19	isupgr 26877	. . 3 ⊢ (𝑆 ∈ V → (𝑆 ∈ UPGraph ↔ (𝐸 ↾ 𝐹):dom (𝐸 ↾ 𝐹)⟶{𝑝 ∈ (𝒫 (𝑉 ∖ {𝑁}) ∖ {∅}) ∣ (♯‘𝑝) ≤ 2}))
21	15, 20	mp1i 13	. 2 ⊢ ((𝐺 ∈ UPGraph ∧ 𝑁 ∈ 𝑉) → (𝑆 ∈ UPGraph ↔ (𝐸 ↾ 𝐹):dom (𝐸 ↾ 𝐹)⟶{𝑝 ∈ (𝒫 (𝑉 ∖ {𝑁}) ∖ {∅}) ∣ (♯‘𝑝) ≤ 2}))
22	12, 21	mpbird 260	1 ⊢ ((𝐺 ∈ UPGraph ∧ 𝑁 ∈ 𝑉) → 𝑆 ∈ UPGraph)

Syntax hints:   → wi 4   ↔ wb 209   ∧ wa 399   = wceq 1538   ∈ wcel 2111   ∉ wnel 3091  {crab 3110  Vcvv 3441   ∖ cdif 3878   ⊆ wss 3881  ∅c0 4243  𝒫 cpw 4497  {csn 4525  ⟨cop 4531   class class class wbr 5030  dom cdm 5519  ran crn 5520   ↾ cres 5521  Fun wfun 6318   Fn wfn 6319  ⟶wf 6320  ‘cfv 6324   ≤ cle 10665  2c2 11680  ♯chash 13686  Vtxcvtx 26789  iEdgciedg 26790  UHGraphcuhgr 26849  UPGraphcupgr 26873

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1797  ax-4 1811  ax-5 1911  ax-6 1970  ax-7 2015  ax-8 2113  ax-9 2121  ax-10 2142  ax-11 2158  ax-12 2175  ax-ext 2770  ax-sep 5167  ax-nul 5174  ax-pow 5231  ax-pr 5295  ax-un 7441

This theorem depends on definitions:  df-bi 210  df-an 400  df-or 845  df-3an 1086  df-tru 1541  df-ex 1782  df-nf 1786  df-sb 2070  df-mo 2598  df-eu 2629  df-clab 2777  df-cleq 2791  df-clel 2870  df-nfc 2938  df-ne 2988  df-nel 3092  df-ral 3111  df-rex 3112  df-rab 3115  df-v 3443  df-sbc 3721  df-dif 3884  df-un 3886  df-in 3888  df-ss 3898  df-nul 4244  df-if 4426  df-pw 4499  df-sn 4526  df-pr 4528  df-op 4532  df-uni 4801  df-br 5031  df-opab 5093  df-mpt 5111  df-id 5425  df-xp 5525  df-rel 5526  df-cnv 5527  df-co 5528  df-dm 5529  df-rn 5530  df-res 5531  df-ima 5532  df-iota 6283  df-fun 6326  df-fn 6327  df-f 6328  df-fv 6332  df-1st 7671  df-2nd 7672  df-vtx 26791  df-iedg 26792  df-uhgr 26851  df-upgr 26875

This theorem is referenced by:  finsumvtxdg2size  27340