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| Mirrors > Home > MPE Home > Th. List > disjiunb | Structured version Visualization version GIF version | ||
| Description: Two ways to say that a collection of index unions 𝐶(𝑖, 𝑥) for 𝑖 ∈ 𝐴 and 𝑥 ∈ 𝐵 is disjoint. (Contributed by AV, 9-Jan-2022.) | 
| Ref | Expression | 
|---|---|
| disjiunb.1 | ⊢ (𝑖 = 𝑗 → 𝐵 = 𝐷) | 
| disjiunb.2 | ⊢ (𝑖 = 𝑗 → 𝐶 = 𝐸) | 
| Ref | Expression | 
|---|---|
| disjiunb | ⊢ (Disj 𝑖 ∈ 𝐴 ∪ 𝑥 ∈ 𝐵 𝐶 ↔ ∀𝑖 ∈ 𝐴 ∀𝑗 ∈ 𝐴 (𝑖 = 𝑗 ∨ (∪ 𝑥 ∈ 𝐵 𝐶 ∩ ∪ 𝑥 ∈ 𝐷 𝐸) = ∅)) | 
| Step | Hyp | Ref | Expression | 
|---|---|---|---|
| 1 | disjiunb.1 | . . 3 ⊢ (𝑖 = 𝑗 → 𝐵 = 𝐷) | |
| 2 | disjiunb.2 | . . 3 ⊢ (𝑖 = 𝑗 → 𝐶 = 𝐸) | |
| 3 | 1, 2 | iuneq12d 5020 | . 2 ⊢ (𝑖 = 𝑗 → ∪ 𝑥 ∈ 𝐵 𝐶 = ∪ 𝑥 ∈ 𝐷 𝐸) | 
| 4 | 3 | disjor 5124 | 1 ⊢ (Disj 𝑖 ∈ 𝐴 ∪ 𝑥 ∈ 𝐵 𝐶 ↔ ∀𝑖 ∈ 𝐴 ∀𝑗 ∈ 𝐴 (𝑖 = 𝑗 ∨ (∪ 𝑥 ∈ 𝐵 𝐶 ∩ ∪ 𝑥 ∈ 𝐷 𝐸) = ∅)) | 
| Colors of variables: wff setvar class | 
| Syntax hints: → wi 4 ↔ wb 206 ∨ wo 847 = wceq 1539 ∀wral 3060 ∩ cin 3949 ∅c0 4332 ∪ ciun 4990 Disj wdisj 5109 | 
| This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1794 ax-4 1808 ax-5 1909 ax-6 1966 ax-7 2006 ax-8 2109 ax-9 2117 ax-11 2156 ax-ext 2707 | 
| This theorem depends on definitions: df-bi 207 df-an 396 df-or 848 df-tru 1542 df-fal 1552 df-ex 1779 df-sb 2064 df-mo 2539 df-clab 2714 df-cleq 2728 df-clel 2815 df-ral 3061 df-rex 3070 df-rmo 3379 df-v 3481 df-dif 3953 df-in 3957 df-ss 3967 df-nul 4333 df-iun 4992 df-disj 5110 | 
| This theorem is referenced by: disjiund 5133 otiunsndisj 5524 s3iunsndisj 15008 | 
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