![]() |
Mathbox for Jeff Madsen |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > MPE Home > Th. List > Mathboxes > welb | Structured version Visualization version GIF version |
Description: A nonempty subset of a well-ordered set has a lower bound. (Contributed by Jeff Madsen, 2-Sep-2009.) |
Ref | Expression |
---|---|
welb | ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → (◡𝑅 Or 𝐵 ∧ ∃𝑥 ∈ 𝐵 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐵 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧)))) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | wess 5253 | . . . . . 6 ⊢ (𝐵 ⊆ 𝐴 → (𝑅 We 𝐴 → 𝑅 We 𝐵)) | |
2 | 1 | impcom 445 | . . . . 5 ⊢ ((𝑅 We 𝐴 ∧ 𝐵 ⊆ 𝐴) → 𝑅 We 𝐵) |
3 | weso 5257 | . . . . 5 ⊢ (𝑅 We 𝐵 → 𝑅 Or 𝐵) | |
4 | 2, 3 | syl 17 | . . . 4 ⊢ ((𝑅 We 𝐴 ∧ 𝐵 ⊆ 𝐴) → 𝑅 Or 𝐵) |
5 | cnvso 5835 | . . . 4 ⊢ (𝑅 Or 𝐵 ↔ ◡𝑅 Or 𝐵) | |
6 | 4, 5 | sylib 208 | . . 3 ⊢ ((𝑅 We 𝐴 ∧ 𝐵 ⊆ 𝐴) → ◡𝑅 Or 𝐵) |
7 | 6 | 3ad2antr2 1205 | . 2 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ◡𝑅 Or 𝐵) |
8 | wefr 5256 | . . . . 5 ⊢ (𝑅 We 𝐵 → 𝑅 Fr 𝐵) | |
9 | 2, 8 | syl 17 | . . . 4 ⊢ ((𝑅 We 𝐴 ∧ 𝐵 ⊆ 𝐴) → 𝑅 Fr 𝐵) |
10 | 9 | 3ad2antr2 1205 | . . 3 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → 𝑅 Fr 𝐵) |
11 | ssid 3765 | . . . . . 6 ⊢ 𝐵 ⊆ 𝐵 | |
12 | 11 | a1i 11 | . . . . 5 ⊢ (𝐵 ⊆ 𝐴 → 𝐵 ⊆ 𝐵) |
13 | 12 | 3anim2i 1157 | . . . 4 ⊢ ((𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅) → (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐵 ∧ 𝐵 ≠ ∅)) |
14 | 13 | adantl 473 | . . 3 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐵 ∧ 𝐵 ≠ ∅)) |
15 | frinfm 33861 | . . 3 ⊢ ((𝑅 Fr 𝐵 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐵 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐵 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐵 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))) | |
16 | 10, 14, 15 | syl2anc 696 | . 2 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐵 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐵 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))) |
17 | 7, 16 | jca 555 | 1 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → (◡𝑅 Or 𝐵 ∧ ∃𝑥 ∈ 𝐵 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐵 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧)))) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ∧ wa 383 ∧ w3a 1072 ∈ wcel 2139 ≠ wne 2932 ∀wral 3050 ∃wrex 3051 ⊆ wss 3715 ∅c0 4058 class class class wbr 4804 Or wor 5186 Fr wfr 5222 We wwe 5224 ◡ccnv 5265 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1871 ax-4 1886 ax-5 1988 ax-6 2054 ax-7 2090 ax-9 2148 ax-10 2168 ax-11 2183 ax-12 2196 ax-13 2391 ax-ext 2740 ax-sep 4933 ax-nul 4941 ax-pr 5055 |
This theorem depends on definitions: df-bi 197 df-or 384 df-an 385 df-3or 1073 df-3an 1074 df-tru 1635 df-ex 1854 df-nf 1859 df-sb 2047 df-eu 2611 df-mo 2612 df-clab 2747 df-cleq 2753 df-clel 2756 df-nfc 2891 df-ne 2933 df-ral 3055 df-rex 3056 df-rab 3059 df-v 3342 df-dif 3718 df-un 3720 df-in 3722 df-ss 3729 df-nul 4059 df-if 4231 df-sn 4322 df-pr 4324 df-op 4328 df-br 4805 df-opab 4865 df-po 5187 df-so 5188 df-fr 5225 df-we 5227 df-cnv 5274 |
This theorem is referenced by: (None) |
Copyright terms: Public domain | W3C validator |