![]() |
Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > ILE Home > Th. List > cnvinfex | GIF version |
Description: Two ways of expressing existence of an infimum (one in terms of converse). (Contributed by Jim Kingdon, 17-Dec-2021.) |
Ref | Expression |
---|---|
cnvinfex.ex | ⊢ (𝜑 → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ 𝐴 (𝑥𝑅𝑦 → ∃𝑧 ∈ 𝐵 𝑧𝑅𝑦))) |
Ref | Expression |
---|---|
cnvinfex | ⊢ (𝜑 → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | cnvinfex.ex | . 2 ⊢ (𝜑 → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ 𝐴 (𝑥𝑅𝑦 → ∃𝑧 ∈ 𝐵 𝑧𝑅𝑦))) | |
2 | vex 2617 | . . . . . . . 8 ⊢ 𝑥 ∈ V | |
3 | vex 2617 | . . . . . . . 8 ⊢ 𝑦 ∈ V | |
4 | 2, 3 | brcnv 4580 | . . . . . . 7 ⊢ (𝑥◡𝑅𝑦 ↔ 𝑦𝑅𝑥) |
5 | 4 | a1i 9 | . . . . . 6 ⊢ (𝜑 → (𝑥◡𝑅𝑦 ↔ 𝑦𝑅𝑥)) |
6 | 5 | notbid 625 | . . . . 5 ⊢ (𝜑 → (¬ 𝑥◡𝑅𝑦 ↔ ¬ 𝑦𝑅𝑥)) |
7 | 6 | ralbidv 2376 | . . . 4 ⊢ (𝜑 → (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ↔ ∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥)) |
8 | 3, 2 | brcnv 4580 | . . . . . . 7 ⊢ (𝑦◡𝑅𝑥 ↔ 𝑥𝑅𝑦) |
9 | 8 | a1i 9 | . . . . . 6 ⊢ (𝜑 → (𝑦◡𝑅𝑥 ↔ 𝑥𝑅𝑦)) |
10 | vex 2617 | . . . . . . . . 9 ⊢ 𝑧 ∈ V | |
11 | 3, 10 | brcnv 4580 | . . . . . . . 8 ⊢ (𝑦◡𝑅𝑧 ↔ 𝑧𝑅𝑦) |
12 | 11 | a1i 9 | . . . . . . 7 ⊢ (𝜑 → (𝑦◡𝑅𝑧 ↔ 𝑧𝑅𝑦)) |
13 | 12 | rexbidv 2377 | . . . . . 6 ⊢ (𝜑 → (∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧 ↔ ∃𝑧 ∈ 𝐵 𝑧𝑅𝑦)) |
14 | 9, 13 | imbi12d 232 | . . . . 5 ⊢ (𝜑 → ((𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧) ↔ (𝑥𝑅𝑦 → ∃𝑧 ∈ 𝐵 𝑧𝑅𝑦))) |
15 | 14 | ralbidv 2376 | . . . 4 ⊢ (𝜑 → (∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧) ↔ ∀𝑦 ∈ 𝐴 (𝑥𝑅𝑦 → ∃𝑧 ∈ 𝐵 𝑧𝑅𝑦))) |
16 | 7, 15 | anbi12d 457 | . . 3 ⊢ (𝜑 → ((∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧)) ↔ (∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ 𝐴 (𝑥𝑅𝑦 → ∃𝑧 ∈ 𝐵 𝑧𝑅𝑦)))) |
17 | 16 | rexbidv 2377 | . 2 ⊢ (𝜑 → (∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧)) ↔ ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑦𝑅𝑥 ∧ ∀𝑦 ∈ 𝐴 (𝑥𝑅𝑦 → ∃𝑧 ∈ 𝐵 𝑧𝑅𝑦)))) |
18 | 1, 17 | mpbird 165 | 1 ⊢ (𝜑 → ∃𝑥 ∈ 𝐴 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐴 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))) |
Colors of variables: wff set class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 102 ↔ wb 103 ∀wral 2355 ∃wrex 2356 class class class wbr 3814 ◡ccnv 4403 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 104 ax-ia2 105 ax-ia3 106 ax-in1 577 ax-in2 578 ax-io 663 ax-5 1379 ax-7 1380 ax-gen 1381 ax-ie1 1425 ax-ie2 1426 ax-8 1438 ax-10 1439 ax-11 1440 ax-i12 1441 ax-bndl 1442 ax-4 1443 ax-14 1448 ax-17 1462 ax-i9 1466 ax-ial 1470 ax-i5r 1471 ax-ext 2067 ax-sep 3925 ax-pow 3977 ax-pr 4003 |
This theorem depends on definitions: df-bi 115 df-3an 924 df-tru 1290 df-nf 1393 df-sb 1690 df-eu 1948 df-mo 1949 df-clab 2072 df-cleq 2078 df-clel 2081 df-nfc 2214 df-ral 2360 df-rex 2361 df-v 2616 df-un 2990 df-in 2992 df-ss 2999 df-pw 3411 df-sn 3431 df-pr 3432 df-op 3434 df-br 3815 df-opab 3869 df-cnv 4412 |
This theorem is referenced by: infvalti 6638 infclti 6639 inflbti 6640 infglbti 6641 infisoti 6648 infrenegsupex 8991 |
Copyright terms: Public domain | W3C validator |