Theorem 0conngr 27965

Description: A graph without vertices is connected. (Contributed by Alexander van der Vekens, 2-Dec-2017.) (Revised by AV, 15-Feb-2021.)

Assertion

Ref	Expression
0conngr	⊢ ∅ ∈ ConnGraph

Proof of Theorem 0conngr

Dummy variables 𝑓 𝑘 𝑛 𝑝 are mutually distinct and distinct from all other variables.

Step	Hyp	Ref	Expression
1		ral0 4456	. 2 ⊢ ∀𝑘 ∈ ∅ ∀𝑛 ∈ ∅ ∃𝑓∃𝑝 𝑓(𝑘(PathsOn‘∅)𝑛)𝑝
2		0ex 5204	. . 3 ⊢ ∅ ∈ V
3		vtxval0 26818	. . . . 5 ⊢ (Vtx‘∅) = ∅
4	3	eqcomi 2830	. . . 4 ⊢ ∅ = (Vtx‘∅)
5	4	isconngr 27962	. . 3 ⊢ (∅ ∈ V → (∅ ∈ ConnGraph ↔ ∀𝑘 ∈ ∅ ∀𝑛 ∈ ∅ ∃𝑓∃𝑝 𝑓(𝑘(PathsOn‘∅)𝑛)𝑝))
6	2, 5	ax-mp 5	. 2 ⊢ (∅ ∈ ConnGraph ↔ ∀𝑘 ∈ ∅ ∀𝑛 ∈ ∅ ∃𝑓∃𝑝 𝑓(𝑘(PathsOn‘∅)𝑛)𝑝)
7	1, 6	mpbir 233	1 ⊢ ∅ ∈ ConnGraph

Syntax hints:   ↔ wb 208  ∃wex 1776   ∈ wcel 2110  ∀wral 3138  Vcvv 3495  ∅c0 4291   class class class wbr 5059  ‘cfv 6350  (class class class)co 7150  Vtxcvtx 26775  PathsOncpthson 27489  ConnGraphcconngr 27959

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 2156  ax-12 2172  ax-ext 2793  ax-sep 5196  ax-nul 5203  ax-pow 5259  ax-pr 5322

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-ne 3017  df-ral 3143  df-rex 3144  df-rab 3147  df-v 3497  df-sbc 3773  df-dif 3939  df-un 3941  df-in 3943  df-ss 3952  df-nul 4292  df-if 4468  df-sn 4562  df-pr 4564  df-op 4568  df-uni 4833  df-br 5060  df-opab 5122  df-mpt 5140  df-id 5455  df-xp 5556  df-rel 5557  df-cnv 5558  df-co 5559  df-dm 5560  df-iota 6309  df-fun 6352  df-fv 6358  df-ov 7153  df-slot 16481  df-base 16483  df-vtx 26777  df-conngr 27960

This theorem is referenced by: (None)