![]() |
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 5297 | . . . . . 6 ⊢ (𝐵 ⊆ 𝐴 → (𝑅 We 𝐴 → 𝑅 We 𝐵)) | |
2 | 1 | impcom 397 | . . . . 5 ⊢ ((𝑅 We 𝐴 ∧ 𝐵 ⊆ 𝐴) → 𝑅 We 𝐵) |
3 | weso 5301 | . . . . 5 ⊢ (𝑅 We 𝐵 → 𝑅 Or 𝐵) | |
4 | 2, 3 | syl 17 | . . . 4 ⊢ ((𝑅 We 𝐴 ∧ 𝐵 ⊆ 𝐴) → 𝑅 Or 𝐵) |
5 | cnvso 5891 | . . . 4 ⊢ (𝑅 Or 𝐵 ↔ ◡𝑅 Or 𝐵) | |
6 | 4, 5 | sylib 210 | . . 3 ⊢ ((𝑅 We 𝐴 ∧ 𝐵 ⊆ 𝐴) → ◡𝑅 Or 𝐵) |
7 | 6 | 3ad2antr2 1241 | . 2 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ◡𝑅 Or 𝐵) |
8 | wefr 5300 | . . . . 5 ⊢ (𝑅 We 𝐵 → 𝑅 Fr 𝐵) | |
9 | 2, 8 | syl 17 | . . . 4 ⊢ ((𝑅 We 𝐴 ∧ 𝐵 ⊆ 𝐴) → 𝑅 Fr 𝐵) |
10 | 9 | 3ad2antr2 1241 | . . 3 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → 𝑅 Fr 𝐵) |
11 | ssidd 3818 | . . . . 5 ⊢ (𝐵 ⊆ 𝐴 → 𝐵 ⊆ 𝐵) | |
12 | 11 | 3anim2i 1193 | . . . 4 ⊢ ((𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅) → (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐵 ∧ 𝐵 ≠ ∅)) |
13 | 12 | adantl 474 | . . 3 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐵 ∧ 𝐵 ≠ ∅)) |
14 | frinfm 34009 | . . 3 ⊢ ((𝑅 Fr 𝐵 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐵 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐵 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐵 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))) | |
15 | 10, 13, 14 | syl2anc 580 | . 2 ⊢ ((𝑅 We 𝐴 ∧ (𝐵 ∈ 𝐶 ∧ 𝐵 ⊆ 𝐴 ∧ 𝐵 ≠ ∅)) → ∃𝑥 ∈ 𝐵 (∀𝑦 ∈ 𝐵 ¬ 𝑥◡𝑅𝑦 ∧ ∀𝑦 ∈ 𝐵 (𝑦◡𝑅𝑥 → ∃𝑧 ∈ 𝐵 𝑦◡𝑅𝑧))) |
16 | 7, 15 | jca 508 | 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 385 ∧ w3a 1108 ∈ wcel 2157 ≠ wne 2969 ∀wral 3087 ∃wrex 3088 ⊆ wss 3767 ∅c0 4113 class class class wbr 4841 Or wor 5230 Fr wfr 5266 We wwe 5268 ◡ccnv 5309 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1891 ax-4 1905 ax-5 2006 ax-6 2072 ax-7 2107 ax-9 2166 ax-10 2185 ax-11 2200 ax-12 2213 ax-13 2375 ax-ext 2775 ax-sep 4973 ax-nul 4981 ax-pr 5095 |
This theorem depends on definitions: df-bi 199 df-an 386 df-or 875 df-3or 1109 df-3an 1110 df-tru 1657 df-ex 1876 df-nf 1880 df-sb 2065 df-mo 2590 df-eu 2607 df-clab 2784 df-cleq 2790 df-clel 2793 df-nfc 2928 df-ne 2970 df-ral 3092 df-rex 3093 df-rab 3096 df-v 3385 df-dif 3770 df-un 3772 df-in 3774 df-ss 3781 df-nul 4114 df-if 4276 df-sn 4367 df-pr 4369 df-op 4373 df-br 4842 df-opab 4904 df-po 5231 df-so 5232 df-fr 5269 df-we 5271 df-cnv 5318 |
This theorem is referenced by: (None) |
Copyright terms: Public domain | W3C validator |