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Mirrors > Home > ILE Home > Th. List > cotr | GIF version |
Description: Two ways of saying a relation is transitive. Definition of transitivity in [Schechter] p. 51. (Contributed by NM, 27-Dec-1996.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
Ref | Expression |
---|---|
cotr | ⊢ ((𝑅 ∘ 𝑅) ⊆ 𝑅 ↔ ∀𝑥∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-co 4548 | . . . 4 ⊢ (𝑅 ∘ 𝑅) = {〈𝑥, 𝑧〉 ∣ ∃𝑦(𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧)} | |
2 | 1 | relopabi 4665 | . . 3 ⊢ Rel (𝑅 ∘ 𝑅) |
3 | ssrel 4627 | . . 3 ⊢ (Rel (𝑅 ∘ 𝑅) → ((𝑅 ∘ 𝑅) ⊆ 𝑅 ↔ ∀𝑥∀𝑧(〈𝑥, 𝑧〉 ∈ (𝑅 ∘ 𝑅) → 〈𝑥, 𝑧〉 ∈ 𝑅))) | |
4 | 2, 3 | ax-mp 5 | . 2 ⊢ ((𝑅 ∘ 𝑅) ⊆ 𝑅 ↔ ∀𝑥∀𝑧(〈𝑥, 𝑧〉 ∈ (𝑅 ∘ 𝑅) → 〈𝑥, 𝑧〉 ∈ 𝑅)) |
5 | vex 2689 | . . . . . . . 8 ⊢ 𝑥 ∈ V | |
6 | vex 2689 | . . . . . . . 8 ⊢ 𝑧 ∈ V | |
7 | 5, 6 | opelco 4711 | . . . . . . 7 ⊢ (〈𝑥, 𝑧〉 ∈ (𝑅 ∘ 𝑅) ↔ ∃𝑦(𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧)) |
8 | df-br 3930 | . . . . . . . 8 ⊢ (𝑥𝑅𝑧 ↔ 〈𝑥, 𝑧〉 ∈ 𝑅) | |
9 | 8 | bicomi 131 | . . . . . . 7 ⊢ (〈𝑥, 𝑧〉 ∈ 𝑅 ↔ 𝑥𝑅𝑧) |
10 | 7, 9 | imbi12i 238 | . . . . . 6 ⊢ ((〈𝑥, 𝑧〉 ∈ (𝑅 ∘ 𝑅) → 〈𝑥, 𝑧〉 ∈ 𝑅) ↔ (∃𝑦(𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) |
11 | 19.23v 1855 | . . . . . 6 ⊢ (∀𝑦((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧) ↔ (∃𝑦(𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) | |
12 | 10, 11 | bitr4i 186 | . . . . 5 ⊢ ((〈𝑥, 𝑧〉 ∈ (𝑅 ∘ 𝑅) → 〈𝑥, 𝑧〉 ∈ 𝑅) ↔ ∀𝑦((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) |
13 | 12 | albii 1446 | . . . 4 ⊢ (∀𝑧(〈𝑥, 𝑧〉 ∈ (𝑅 ∘ 𝑅) → 〈𝑥, 𝑧〉 ∈ 𝑅) ↔ ∀𝑧∀𝑦((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) |
14 | alcom 1454 | . . . 4 ⊢ (∀𝑧∀𝑦((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧) ↔ ∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) | |
15 | 13, 14 | bitri 183 | . . 3 ⊢ (∀𝑧(〈𝑥, 𝑧〉 ∈ (𝑅 ∘ 𝑅) → 〈𝑥, 𝑧〉 ∈ 𝑅) ↔ ∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) |
16 | 15 | albii 1446 | . 2 ⊢ (∀𝑥∀𝑧(〈𝑥, 𝑧〉 ∈ (𝑅 ∘ 𝑅) → 〈𝑥, 𝑧〉 ∈ 𝑅) ↔ ∀𝑥∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) |
17 | 4, 16 | bitri 183 | 1 ⊢ ((𝑅 ∘ 𝑅) ⊆ 𝑅 ↔ ∀𝑥∀𝑦∀𝑧((𝑥𝑅𝑦 ∧ 𝑦𝑅𝑧) → 𝑥𝑅𝑧)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ↔ wb 104 ∀wal 1329 ∃wex 1468 ∈ wcel 1480 ⊆ wss 3071 〈cop 3530 class class class wbr 3929 ∘ ccom 4543 Rel wrel 4544 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-io 698 ax-5 1423 ax-7 1424 ax-gen 1425 ax-ie1 1469 ax-ie2 1470 ax-8 1482 ax-10 1483 ax-11 1484 ax-i12 1485 ax-bndl 1486 ax-4 1487 ax-14 1492 ax-17 1506 ax-i9 1510 ax-ial 1514 ax-i5r 1515 ax-ext 2121 ax-sep 4046 ax-pow 4098 ax-pr 4131 |
This theorem depends on definitions: df-bi 116 df-3an 964 df-tru 1334 df-nf 1437 df-sb 1736 df-eu 2002 df-mo 2003 df-clab 2126 df-cleq 2132 df-clel 2135 df-nfc 2270 df-ral 2421 df-rex 2422 df-v 2688 df-un 3075 df-in 3077 df-ss 3084 df-pw 3512 df-sn 3533 df-pr 3534 df-op 3536 df-br 3930 df-opab 3990 df-xp 4545 df-rel 4546 df-co 4548 |
This theorem is referenced by: xpidtr 4929 trin2 4930 dfer2 6430 |
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