Mathbox for Steven Nguyen |
< Previous
Next >
Nearby theorems |
||
Mirrors > Home > MPE Home > Th. List > Mathboxes > infdesc | Structured version Visualization version GIF version |
Description: Infinite descent. The hypotheses say that 𝑆 is lower bounded, and that if 𝜓 holds for an integer in 𝑆, it holds for a smaller integer in 𝑆. By infinite descent, eventually we cannot go any smaller, therefore 𝜓 holds for no integer in 𝑆. (Contributed by SN, 20-Aug-2024.) |
Ref | Expression |
---|---|
infdesc.x | ⊢ (𝑦 = 𝑥 → (𝜓 ↔ 𝜒)) |
infdesc.z | ⊢ (𝑦 = 𝑧 → (𝜓 ↔ 𝜃)) |
infdesc.s | ⊢ (𝜑 → 𝑆 ⊆ (ℤ≥‘𝑀)) |
infdesc.1 | ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑆 ∧ 𝜒)) → ∃𝑧 ∈ 𝑆 (𝜃 ∧ 𝑧 < 𝑥)) |
Ref | Expression |
---|---|
infdesc | ⊢ (𝜑 → {𝑦 ∈ 𝑆 ∣ 𝜓} = ∅) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | df-ne 2942 | . . 3 ⊢ ({𝑦 ∈ 𝑆 ∣ 𝜓} ≠ ∅ ↔ ¬ {𝑦 ∈ 𝑆 ∣ 𝜓} = ∅) | |
2 | ssrab2 4008 | . . . . . 6 ⊢ {𝑦 ∈ 𝑆 ∣ 𝜓} ⊆ 𝑆 | |
3 | infdesc.s | . . . . . 6 ⊢ (𝜑 → 𝑆 ⊆ (ℤ≥‘𝑀)) | |
4 | 2, 3 | sstrid 3927 | . . . . 5 ⊢ (𝜑 → {𝑦 ∈ 𝑆 ∣ 𝜓} ⊆ (ℤ≥‘𝑀)) |
5 | uzwo 12532 | . . . . 5 ⊢ (({𝑦 ∈ 𝑆 ∣ 𝜓} ⊆ (ℤ≥‘𝑀) ∧ {𝑦 ∈ 𝑆 ∣ 𝜓} ≠ ∅) → ∃𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧) | |
6 | 4, 5 | sylan 583 | . . . 4 ⊢ ((𝜑 ∧ {𝑦 ∈ 𝑆 ∣ 𝜓} ≠ ∅) → ∃𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧) |
7 | infdesc.x | . . . . . . . . . 10 ⊢ (𝑦 = 𝑥 → (𝜓 ↔ 𝜒)) | |
8 | 7 | elrab 3615 | . . . . . . . . 9 ⊢ (𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ↔ (𝑥 ∈ 𝑆 ∧ 𝜒)) |
9 | infdesc.1 | . . . . . . . . . 10 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑆 ∧ 𝜒)) → ∃𝑧 ∈ 𝑆 (𝜃 ∧ 𝑧 < 𝑥)) | |
10 | uzssre 12485 | . . . . . . . . . . . . . . . . 17 ⊢ (ℤ≥‘𝑀) ⊆ ℝ | |
11 | 3, 10 | sstrdi 3928 | . . . . . . . . . . . . . . . 16 ⊢ (𝜑 → 𝑆 ⊆ ℝ) |
12 | 11 | adantr 484 | . . . . . . . . . . . . . . 15 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝑆) → 𝑆 ⊆ ℝ) |
13 | 12 | sselda 3916 | . . . . . . . . . . . . . 14 ⊢ (((𝜑 ∧ 𝑥 ∈ 𝑆) ∧ 𝑧 ∈ 𝑆) → 𝑧 ∈ ℝ) |
14 | 11 | sselda 3916 | . . . . . . . . . . . . . . 15 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝑆) → 𝑥 ∈ ℝ) |
15 | 14 | adantr 484 | . . . . . . . . . . . . . 14 ⊢ (((𝜑 ∧ 𝑥 ∈ 𝑆) ∧ 𝑧 ∈ 𝑆) → 𝑥 ∈ ℝ) |
16 | 13, 15 | ltnled 11004 | . . . . . . . . . . . . 13 ⊢ (((𝜑 ∧ 𝑥 ∈ 𝑆) ∧ 𝑧 ∈ 𝑆) → (𝑧 < 𝑥 ↔ ¬ 𝑥 ≤ 𝑧)) |
17 | 16 | anbi2d 632 | . . . . . . . . . . . 12 ⊢ (((𝜑 ∧ 𝑥 ∈ 𝑆) ∧ 𝑧 ∈ 𝑆) → ((𝜃 ∧ 𝑧 < 𝑥) ↔ (𝜃 ∧ ¬ 𝑥 ≤ 𝑧))) |
18 | 17 | rexbidva 3223 | . . . . . . . . . . 11 ⊢ ((𝜑 ∧ 𝑥 ∈ 𝑆) → (∃𝑧 ∈ 𝑆 (𝜃 ∧ 𝑧 < 𝑥) ↔ ∃𝑧 ∈ 𝑆 (𝜃 ∧ ¬ 𝑥 ≤ 𝑧))) |
19 | 18 | adantrr 717 | . . . . . . . . . 10 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑆 ∧ 𝜒)) → (∃𝑧 ∈ 𝑆 (𝜃 ∧ 𝑧 < 𝑥) ↔ ∃𝑧 ∈ 𝑆 (𝜃 ∧ ¬ 𝑥 ≤ 𝑧))) |
20 | 9, 19 | mpbid 235 | . . . . . . . . 9 ⊢ ((𝜑 ∧ (𝑥 ∈ 𝑆 ∧ 𝜒)) → ∃𝑧 ∈ 𝑆 (𝜃 ∧ ¬ 𝑥 ≤ 𝑧)) |
21 | 8, 20 | sylan2b 597 | . . . . . . . 8 ⊢ ((𝜑 ∧ 𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}) → ∃𝑧 ∈ 𝑆 (𝜃 ∧ ¬ 𝑥 ≤ 𝑧)) |
22 | infdesc.z | . . . . . . . . 9 ⊢ (𝑦 = 𝑧 → (𝜓 ↔ 𝜃)) | |
23 | 22 | rexrab 3624 | . . . . . . . 8 ⊢ (∃𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ¬ 𝑥 ≤ 𝑧 ↔ ∃𝑧 ∈ 𝑆 (𝜃 ∧ ¬ 𝑥 ≤ 𝑧)) |
24 | 21, 23 | sylibr 237 | . . . . . . 7 ⊢ ((𝜑 ∧ 𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}) → ∃𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ¬ 𝑥 ≤ 𝑧) |
25 | 24 | ralrimiva 3106 | . . . . . 6 ⊢ (𝜑 → ∀𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∃𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ¬ 𝑥 ≤ 𝑧) |
26 | rexnal 3164 | . . . . . . . 8 ⊢ (∃𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ¬ 𝑥 ≤ 𝑧 ↔ ¬ ∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧) | |
27 | 26 | ralbii 3089 | . . . . . . 7 ⊢ (∀𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∃𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ¬ 𝑥 ≤ 𝑧 ↔ ∀𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ¬ ∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧) |
28 | ralnex 3162 | . . . . . . 7 ⊢ (∀𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ¬ ∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧 ↔ ¬ ∃𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧) | |
29 | 27, 28 | bitri 278 | . . . . . 6 ⊢ (∀𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∃𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓} ¬ 𝑥 ≤ 𝑧 ↔ ¬ ∃𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧) |
30 | 25, 29 | sylib 221 | . . . . 5 ⊢ (𝜑 → ¬ ∃𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧) |
31 | 30 | adantr 484 | . . . 4 ⊢ ((𝜑 ∧ {𝑦 ∈ 𝑆 ∣ 𝜓} ≠ ∅) → ¬ ∃𝑥 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}∀𝑧 ∈ {𝑦 ∈ 𝑆 ∣ 𝜓}𝑥 ≤ 𝑧) |
32 | 6, 31 | pm2.21dd 198 | . . 3 ⊢ ((𝜑 ∧ {𝑦 ∈ 𝑆 ∣ 𝜓} ≠ ∅) → {𝑦 ∈ 𝑆 ∣ 𝜓} = ∅) |
33 | 1, 32 | sylan2br 598 | . 2 ⊢ ((𝜑 ∧ ¬ {𝑦 ∈ 𝑆 ∣ 𝜓} = ∅) → {𝑦 ∈ 𝑆 ∣ 𝜓} = ∅) |
34 | 33 | pm2.18da 800 | 1 ⊢ (𝜑 → {𝑦 ∈ 𝑆 ∣ 𝜓} = ∅) |
Colors of variables: wff setvar class |
Syntax hints: ¬ wn 3 → wi 4 ↔ wb 209 ∧ wa 399 = wceq 1543 ∈ wcel 2111 ≠ wne 2941 ∀wral 3062 ∃wrex 3063 {crab 3066 ⊆ wss 3881 ∅c0 4252 class class class wbr 5068 ‘cfv 6398 ℝcr 10753 < clt 10892 ≤ cle 10893 ℤ≥cuz 12463 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1803 ax-4 1817 ax-5 1918 ax-6 1976 ax-7 2016 ax-8 2113 ax-9 2121 ax-10 2142 ax-11 2159 ax-12 2176 ax-ext 2709 ax-sep 5207 ax-nul 5214 ax-pow 5273 ax-pr 5337 ax-un 7542 ax-cnex 10810 ax-resscn 10811 ax-1cn 10812 ax-icn 10813 ax-addcl 10814 ax-addrcl 10815 ax-mulcl 10816 ax-mulrcl 10817 ax-mulcom 10818 ax-addass 10819 ax-mulass 10820 ax-distr 10821 ax-i2m1 10822 ax-1ne0 10823 ax-1rid 10824 ax-rnegex 10825 ax-rrecex 10826 ax-cnre 10827 ax-pre-lttri 10828 ax-pre-lttrn 10829 ax-pre-ltadd 10830 ax-pre-mulgt0 10831 |
This theorem depends on definitions: df-bi 210 df-an 400 df-or 848 df-3or 1090 df-3an 1091 df-tru 1546 df-fal 1556 df-ex 1788 df-nf 1792 df-sb 2072 df-mo 2540 df-eu 2569 df-clab 2716 df-cleq 2730 df-clel 2817 df-nfc 2887 df-ne 2942 df-nel 3048 df-ral 3067 df-rex 3068 df-reu 3069 df-rab 3071 df-v 3423 df-sbc 3710 df-csb 3827 df-dif 3884 df-un 3886 df-in 3888 df-ss 3898 df-pss 3900 df-nul 4253 df-if 4455 df-pw 4530 df-sn 4557 df-pr 4559 df-tp 4561 df-op 4563 df-uni 4835 df-iun 4921 df-br 5069 df-opab 5131 df-mpt 5151 df-tr 5177 df-id 5470 df-eprel 5475 df-po 5483 df-so 5484 df-fr 5524 df-we 5526 df-xp 5572 df-rel 5573 df-cnv 5574 df-co 5575 df-dm 5576 df-rn 5577 df-res 5578 df-ima 5579 df-pred 6176 df-ord 6234 df-on 6235 df-lim 6236 df-suc 6237 df-iota 6356 df-fun 6400 df-fn 6401 df-f 6402 df-f1 6403 df-fo 6404 df-f1o 6405 df-fv 6406 df-riota 7189 df-ov 7235 df-oprab 7236 df-mpo 7237 df-om 7664 df-wrecs 8068 df-recs 8129 df-rdg 8167 df-er 8412 df-en 8648 df-dom 8649 df-sdom 8650 df-pnf 10894 df-mnf 10895 df-xr 10896 df-ltxr 10897 df-le 10898 df-sub 11089 df-neg 11090 df-nn 11856 df-n0 12116 df-z 12202 df-uz 12464 |
This theorem is referenced by: nna4b4nsq 40233 |
Copyright terms: Public domain | W3C validator |