Theorem disjord 5061

Description: Conditions for a collection of sets 𝐴(𝑎) for 𝑎 ∈ 𝑉 to be disjoint. (Contributed by AV, 9-Jan-2022.)

Hypotheses

Ref	Expression
disjord.1	⊢ (𝑎 = 𝑏 → 𝐴 = 𝐵)
disjord.2	⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵) → 𝑎 = 𝑏)

Assertion

Ref	Expression
disjord	⊢ (𝜑 → Disj 𝑎 ∈ 𝑉 𝐴)

Distinct variable groups:   𝐴,𝑏,𝑥   𝐵,𝑎,𝑥   𝑉,𝑎,𝑏,𝑥   𝜑,𝑎,𝑏,𝑥

Allowed substitution hints:   𝐴(𝑎)   𝐵(𝑏)

Proof of Theorem disjord

Step	Hyp	Ref	Expression
1		orc 873	. . . . . 6 ⊢ (𝑎 = 𝑏 → (𝑎 = 𝑏 ∨ (𝐴 ∩ 𝐵) = ∅))
2	1	a1d 25	. . . . 5 ⊢ (𝑎 = 𝑏 → (𝜑 → (𝑎 = 𝑏 ∨ (𝐴 ∩ 𝐵) = ∅)))
3		disjord.2	. . . . . . . . . . . 12 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴 ∧ 𝑥 ∈ 𝐵) → 𝑎 = 𝑏)
4	3	3expia 1127	. . . . . . . . . . 11 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (𝑥 ∈ 𝐵 → 𝑎 = 𝑏))
5	4	con3d 152	. . . . . . . . . 10 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝐴) → (¬ 𝑎 = 𝑏 → ¬ 𝑥 ∈ 𝐵))
6	5	impancom 452	. . . . . . . . 9 ⊢ ((𝜑 ∧ ¬ 𝑎 = 𝑏) → (𝑥 ∈ 𝐴 → ¬ 𝑥 ∈ 𝐵))
7	6	ralrimiv 3130	. . . . . . . 8 ⊢ ((𝜑 ∧ ¬ 𝑎 = 𝑏) → ∀𝑥 ∈ 𝐴 ¬ 𝑥 ∈ 𝐵)
8		disj 4378	. . . . . . . 8 ⊢ ((𝐴 ∩ 𝐵) = ∅ ↔ ∀𝑥 ∈ 𝐴 ¬ 𝑥 ∈ 𝐵)
9	7, 8	sylibr 235	. . . . . . 7 ⊢ ((𝜑 ∧ ¬ 𝑎 = 𝑏) → (𝐴 ∩ 𝐵) = ∅)
10	9	olcd 880	. . . . . 6 ⊢ ((𝜑 ∧ ¬ 𝑎 = 𝑏) → (𝑎 = 𝑏 ∨ (𝐴 ∩ 𝐵) = ∅))
11	10	expcom 414	. . . . 5 ⊢ (¬ 𝑎 = 𝑏 → (𝜑 → (𝑎 = 𝑏 ∨ (𝐴 ∩ 𝐵) = ∅)))
12	2, 11	pm2.61i 183	. . . 4 ⊢ (𝜑 → (𝑎 = 𝑏 ∨ (𝐴 ∩ 𝐵) = ∅))
13	12	adantr 481	. . 3 ⊢ ((𝜑 ∧ (𝑎 ∈ 𝑉 ∧ 𝑏 ∈ 𝑉)) → (𝑎 = 𝑏 ∨ (𝐴 ∩ 𝐵) = ∅))
14	13	ralrimivva 3182	. 2 ⊢ (𝜑 → ∀𝑎 ∈ 𝑉 ∀𝑏 ∈ 𝑉 (𝑎 = 𝑏 ∨ (𝐴 ∩ 𝐵) = ∅))
15		disjord.1	. . 3 ⊢ (𝑎 = 𝑏 → 𝐴 = 𝐵)
16	15	disjor 5054	. 2 ⊢ (Disj 𝑎 ∈ 𝑉 𝐴 ↔ ∀𝑎 ∈ 𝑉 ∀𝑏 ∈ 𝑉 (𝑎 = 𝑏 ∨ (𝐴 ∩ 𝐵) = ∅))
17	14, 16	sylibr 235	1 ⊢ (𝜑 → Disj 𝑎 ∈ 𝑉 𝐴)

Syntax hints:  ¬ wn 3   → wi 4   ∧ wa 396   ∨ wo 853   ∧ w3a 1092   = wceq 1547   ∈ wcel 2119  ∀wral 3053   ∩ cin 3882  ∅c0 4261  Disj wdisj 5039

This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1802  ax-4 1816  ax-5 1917  ax-6 1974  ax-7 2015  ax-8 2121  ax-9 2129  ax-11 2168  ax-ext 2711

This theorem depends on definitions:  df-bi 208  df-an 397  df-or 854  df-3an 1094  df-tru 1550  df-fal 1560  df-ex 1787  df-sb 2074  df-mo 2543  df-clab 2718  df-cleq 2731  df-clel 2814  df-ral 3054  df-rmo 3344  df-v 3433  df-dif 3886  df-in 3890  df-nul 4262  df-disj 5040

This theorem is referenced by:  2wspdisj  30051