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Mirrors > Home > ILE Home > Th. List > cnvsym | GIF version |
Description: Two ways of saying a relation is symmetric. Similar to definition of symmetry in [Schechter] p. 51. (Contributed by NM, 28-Dec-1996.) (Proof shortened by Andrew Salmon, 27-Aug-2011.) |
Ref | Expression |
---|---|
cnvsym | ⊢ (◡𝑅 ⊆ 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | alcom 1454 | . 2 ⊢ (∀𝑦∀𝑥(〈𝑦, 𝑥〉 ∈ ◡𝑅 → 〈𝑦, 𝑥〉 ∈ 𝑅) ↔ ∀𝑥∀𝑦(〈𝑦, 𝑥〉 ∈ ◡𝑅 → 〈𝑦, 𝑥〉 ∈ 𝑅)) | |
2 | relcnv 4912 | . . 3 ⊢ Rel ◡𝑅 | |
3 | ssrel 4622 | . . 3 ⊢ (Rel ◡𝑅 → (◡𝑅 ⊆ 𝑅 ↔ ∀𝑦∀𝑥(〈𝑦, 𝑥〉 ∈ ◡𝑅 → 〈𝑦, 𝑥〉 ∈ 𝑅))) | |
4 | 2, 3 | ax-mp 5 | . 2 ⊢ (◡𝑅 ⊆ 𝑅 ↔ ∀𝑦∀𝑥(〈𝑦, 𝑥〉 ∈ ◡𝑅 → 〈𝑦, 𝑥〉 ∈ 𝑅)) |
5 | vex 2684 | . . . . . 6 ⊢ 𝑦 ∈ V | |
6 | vex 2684 | . . . . . 6 ⊢ 𝑥 ∈ V | |
7 | 5, 6 | brcnv 4717 | . . . . 5 ⊢ (𝑦◡𝑅𝑥 ↔ 𝑥𝑅𝑦) |
8 | df-br 3925 | . . . . 5 ⊢ (𝑦◡𝑅𝑥 ↔ 〈𝑦, 𝑥〉 ∈ ◡𝑅) | |
9 | 7, 8 | bitr3i 185 | . . . 4 ⊢ (𝑥𝑅𝑦 ↔ 〈𝑦, 𝑥〉 ∈ ◡𝑅) |
10 | df-br 3925 | . . . 4 ⊢ (𝑦𝑅𝑥 ↔ 〈𝑦, 𝑥〉 ∈ 𝑅) | |
11 | 9, 10 | imbi12i 238 | . . 3 ⊢ ((𝑥𝑅𝑦 → 𝑦𝑅𝑥) ↔ (〈𝑦, 𝑥〉 ∈ ◡𝑅 → 〈𝑦, 𝑥〉 ∈ 𝑅)) |
12 | 11 | 2albii 1447 | . 2 ⊢ (∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥) ↔ ∀𝑥∀𝑦(〈𝑦, 𝑥〉 ∈ ◡𝑅 → 〈𝑦, 𝑥〉 ∈ 𝑅)) |
13 | 1, 4, 12 | 3bitr4i 211 | 1 ⊢ (◡𝑅 ⊆ 𝑅 ↔ ∀𝑥∀𝑦(𝑥𝑅𝑦 → 𝑦𝑅𝑥)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 104 ∀wal 1329 ∈ wcel 1480 ⊆ wss 3066 〈cop 3525 class class class wbr 3924 ◡ccnv 4533 Rel wrel 4539 |
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 2119 ax-sep 4041 ax-pow 4093 ax-pr 4126 |
This theorem depends on definitions: df-bi 116 df-3an 964 df-tru 1334 df-nf 1437 df-sb 1736 df-eu 2000 df-mo 2001 df-clab 2124 df-cleq 2130 df-clel 2133 df-nfc 2268 df-ral 2419 df-rex 2420 df-v 2683 df-un 3070 df-in 3072 df-ss 3079 df-pw 3507 df-sn 3528 df-pr 3529 df-op 3531 df-br 3925 df-opab 3985 df-xp 4540 df-rel 4541 df-cnv 4542 |
This theorem is referenced by: dfer2 6423 |
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