![]() |
Intuitionistic Logic Explorer |
< Previous
Next >
Nearby theorems |
|
Mirrors > Home > ILE Home > Th. List > nnrecl | GIF version |
Description: There exists a positive integer whose reciprocal is less than a given positive real. Exercise 3 of [Apostol] p. 28. (Contributed by NM, 8-Nov-2004.) |
Ref | Expression |
---|---|
nnrecl | ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → ∃𝑛 ∈ ℕ (1 / 𝑛) < 𝐴) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | simpl 108 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 𝐴 ∈ ℝ) | |
2 | gt0ap0 8306 | . . . 4 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 𝐴 # 0) | |
3 | 1, 2 | rerecclapd 8506 | . . 3 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → (1 / 𝐴) ∈ ℝ) |
4 | arch 8878 | . . 3 ⊢ ((1 / 𝐴) ∈ ℝ → ∃𝑛 ∈ ℕ (1 / 𝐴) < 𝑛) | |
5 | 3, 4 | syl 14 | . 2 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → ∃𝑛 ∈ ℕ (1 / 𝐴) < 𝑛) |
6 | recgt0 8518 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 0 < (1 / 𝐴)) | |
7 | 3, 6 | jca 302 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → ((1 / 𝐴) ∈ ℝ ∧ 0 < (1 / 𝐴))) |
8 | nnre 8637 | . . . . . 6 ⊢ (𝑛 ∈ ℕ → 𝑛 ∈ ℝ) | |
9 | nngt0 8655 | . . . . . 6 ⊢ (𝑛 ∈ ℕ → 0 < 𝑛) | |
10 | 8, 9 | jca 302 | . . . . 5 ⊢ (𝑛 ∈ ℕ → (𝑛 ∈ ℝ ∧ 0 < 𝑛)) |
11 | ltrec 8551 | . . . . 5 ⊢ ((((1 / 𝐴) ∈ ℝ ∧ 0 < (1 / 𝐴)) ∧ (𝑛 ∈ ℝ ∧ 0 < 𝑛)) → ((1 / 𝐴) < 𝑛 ↔ (1 / 𝑛) < (1 / (1 / 𝐴)))) | |
12 | 7, 10, 11 | syl2an 285 | . . . 4 ⊢ (((𝐴 ∈ ℝ ∧ 0 < 𝐴) ∧ 𝑛 ∈ ℕ) → ((1 / 𝐴) < 𝑛 ↔ (1 / 𝑛) < (1 / (1 / 𝐴)))) |
13 | recn 7677 | . . . . . . . 8 ⊢ (𝐴 ∈ ℝ → 𝐴 ∈ ℂ) | |
14 | 13 | adantr 272 | . . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → 𝐴 ∈ ℂ) |
15 | 14, 2 | recrecapd 8458 | . . . . . 6 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → (1 / (1 / 𝐴)) = 𝐴) |
16 | 15 | breq2d 3907 | . . . . 5 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → ((1 / 𝑛) < (1 / (1 / 𝐴)) ↔ (1 / 𝑛) < 𝐴)) |
17 | 16 | adantr 272 | . . . 4 ⊢ (((𝐴 ∈ ℝ ∧ 0 < 𝐴) ∧ 𝑛 ∈ ℕ) → ((1 / 𝑛) < (1 / (1 / 𝐴)) ↔ (1 / 𝑛) < 𝐴)) |
18 | 12, 17 | bitrd 187 | . . 3 ⊢ (((𝐴 ∈ ℝ ∧ 0 < 𝐴) ∧ 𝑛 ∈ ℕ) → ((1 / 𝐴) < 𝑛 ↔ (1 / 𝑛) < 𝐴)) |
19 | 18 | rexbidva 2408 | . 2 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → (∃𝑛 ∈ ℕ (1 / 𝐴) < 𝑛 ↔ ∃𝑛 ∈ ℕ (1 / 𝑛) < 𝐴)) |
20 | 5, 19 | mpbid 146 | 1 ⊢ ((𝐴 ∈ ℝ ∧ 0 < 𝐴) → ∃𝑛 ∈ ℕ (1 / 𝑛) < 𝐴) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ∧ wa 103 ↔ wb 104 ∈ wcel 1463 ∃wrex 2391 class class class wbr 3895 (class class class)co 5728 ℂcc 7545 ℝcr 7546 0cc0 7547 1c1 7548 < clt 7724 / cdiv 8345 ℕcn 8630 |
This theorem was proved from axioms: ax-1 5 ax-2 6 ax-mp 7 ax-ia1 105 ax-ia2 106 ax-ia3 107 ax-in1 586 ax-in2 587 ax-io 681 ax-5 1406 ax-7 1407 ax-gen 1408 ax-ie1 1452 ax-ie2 1453 ax-8 1465 ax-10 1466 ax-11 1467 ax-i12 1468 ax-bndl 1469 ax-4 1470 ax-13 1474 ax-14 1475 ax-17 1489 ax-i9 1493 ax-ial 1497 ax-i5r 1498 ax-ext 2097 ax-sep 4006 ax-pow 4058 ax-pr 4091 ax-un 4315 ax-setind 4412 ax-cnex 7636 ax-resscn 7637 ax-1cn 7638 ax-1re 7639 ax-icn 7640 ax-addcl 7641 ax-addrcl 7642 ax-mulcl 7643 ax-mulrcl 7644 ax-addcom 7645 ax-mulcom 7646 ax-addass 7647 ax-mulass 7648 ax-distr 7649 ax-i2m1 7650 ax-0lt1 7651 ax-1rid 7652 ax-0id 7653 ax-rnegex 7654 ax-precex 7655 ax-cnre 7656 ax-pre-ltirr 7657 ax-pre-ltwlin 7658 ax-pre-lttrn 7659 ax-pre-apti 7660 ax-pre-ltadd 7661 ax-pre-mulgt0 7662 ax-pre-mulext 7663 ax-arch 7664 |
This theorem depends on definitions: df-bi 116 df-3an 947 df-tru 1317 df-fal 1320 df-nf 1420 df-sb 1719 df-eu 1978 df-mo 1979 df-clab 2102 df-cleq 2108 df-clel 2111 df-nfc 2244 df-ne 2283 df-nel 2378 df-ral 2395 df-rex 2396 df-reu 2397 df-rmo 2398 df-rab 2399 df-v 2659 df-sbc 2879 df-dif 3039 df-un 3041 df-in 3043 df-ss 3050 df-pw 3478 df-sn 3499 df-pr 3500 df-op 3502 df-uni 3703 df-int 3738 df-br 3896 df-opab 3950 df-id 4175 df-po 4178 df-iso 4179 df-xp 4505 df-rel 4506 df-cnv 4507 df-co 4508 df-dm 4509 df-iota 5046 df-fun 5083 df-fv 5089 df-riota 5684 df-ov 5731 df-oprab 5732 df-mpo 5733 df-pnf 7726 df-mnf 7727 df-xr 7728 df-ltxr 7729 df-le 7730 df-sub 7858 df-neg 7859 df-reap 8255 df-ap 8262 df-div 8346 df-inn 8631 |
This theorem is referenced by: qbtwnre 9927 trilpolemlt1 12926 |
Copyright terms: Public domain | W3C validator |