Theorem frgrwopreglem1 27292

Description: Lemma 1 for frgrwopreg 27303: the classes 𝐴 and 𝐵 are sets. The definition of 𝐴 and 𝐵 corresponds to definition 3 in [Huneke] p. 2: "Let A be the set of all vertices of degree k, let B be the set of all vertices of degree different from k, ..." (Contributed by Alexander van der Vekens, 31-Dec-2017.) (Revised by AV, 10-May-2021.)

Hypotheses

Ref	Expression
frgrwopreg.v	⊢ 𝑉 = (Vtx‘𝐺)
frgrwopreg.d	⊢ 𝐷 = (VtxDeg‘𝐺)
frgrwopreg.a	⊢ 𝐴 = {𝑥 ∈ 𝑉 ∣ (𝐷‘𝑥) = 𝐾}
frgrwopreg.b	⊢ 𝐵 = (𝑉 ∖ 𝐴)

Assertion

Ref	Expression
frgrwopreglem1	⊢ (𝐴 ∈ V ∧ 𝐵 ∈ V)

Distinct variable group:   𝑥,𝑉

Allowed substitution hints:   𝐴(𝑥)   𝐵(𝑥)   𝐷(𝑥)   𝐺(𝑥)   𝐾(𝑥)

Proof of Theorem frgrwopreglem1

Step	Hyp	Ref	Expression
1		frgrwopreg.v	. . 3 ⊢ 𝑉 = (Vtx‘𝐺)
2		fvex 6239	. . 3 ⊢ (Vtx‘𝐺) ∈ V
3	1, 2	eqeltri 2726	. 2 ⊢ 𝑉 ∈ V
4		frgrwopreg.a	. . . 4 ⊢ 𝐴 = {𝑥 ∈ 𝑉 ∣ (𝐷‘𝑥) = 𝐾}
5		rabexg 4844	. . . 4 ⊢ (𝑉 ∈ V → {𝑥 ∈ 𝑉 ∣ (𝐷‘𝑥) = 𝐾} ∈ V)
6	4, 5	syl5eqel 2734	. . 3 ⊢ (𝑉 ∈ V → 𝐴 ∈ V)
7		frgrwopreg.b	. . . 4 ⊢ 𝐵 = (𝑉 ∖ 𝐴)
8		difexg 4841	. . . 4 ⊢ (𝑉 ∈ V → (𝑉 ∖ 𝐴) ∈ V)
9	7, 8	syl5eqel 2734	. . 3 ⊢ (𝑉 ∈ V → 𝐵 ∈ V)
10	6, 9	jca 553	. 2 ⊢ (𝑉 ∈ V → (𝐴 ∈ V ∧ 𝐵 ∈ V))
11	3, 10	ax-mp 5	1 ⊢ (𝐴 ∈ V ∧ 𝐵 ∈ V)

Syntax hints:   ∧ wa 383   = wceq 1523   ∈ wcel 2030  {crab 2945  Vcvv 3231   ∖ cdif 3604  ‘cfv 5926  Vtxcvtx 25919  VtxDegcvtxdg 26417

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1762  ax-4 1777  ax-5 1879  ax-6 1945  ax-7 1981  ax-9 2039  ax-10 2059  ax-11 2074  ax-12 2087  ax-13 2282  ax-ext 2631  ax-sep 4814  ax-nul 4822

This theorem depends on definitions:  df-bi 197  df-or 384  df-an 385  df-tru 1526  df-ex 1745  df-nf 1750  df-sb 1938  df-eu 2502  df-clab 2638  df-cleq 2644  df-clel 2647  df-nfc 2782  df-ral 2946  df-rex 2947  df-rab 2950  df-v 3233  df-sbc 3469  df-dif 3610  df-un 3612  df-in 3614  df-ss 3621  df-nul 3949  df-sn 4211  df-pr 4213  df-uni 4469  df-iota 5889  df-fv 5934

This theorem is referenced by:  frgrwopreg2  27299  frgrwopreglem5  27301  frgrwopreglem5ALT  27302  frgrwopreg  27303