Proof of Theorem caubnd2
| Step | Hyp | Ref
 | Expression | 
| 1 |   | 1rp 9732 | 
. . 3
⊢ 1 ∈
ℝ+ | 
| 2 |   | breq2 4037 | 
. . . . . 6
⊢ (𝑥 = 1 → ((abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 𝑥 ↔ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1)) | 
| 3 | 2 | anbi2d 464 | 
. . . . 5
⊢ (𝑥 = 1 → (((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 𝑥) ↔ ((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1))) | 
| 4 | 3 | rexralbidv 2523 | 
. . . 4
⊢ (𝑥 = 1 → (∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 𝑥) ↔ ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1))) | 
| 5 | 4 | rspcv 2864 | 
. . 3
⊢ (1 ∈
ℝ+ → (∀𝑥 ∈ ℝ+ ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 𝑥) → ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1))) | 
| 6 | 1, 5 | ax-mp 5 | 
. 2
⊢
(∀𝑥 ∈
ℝ+ ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 𝑥) → ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1)) | 
| 7 |   | eluzelz 9610 | 
. . . . . . . . . . 11
⊢ (𝑗 ∈
(ℤ≥‘𝑀) → 𝑗 ∈ ℤ) | 
| 8 |   | cau3.1 | 
. . . . . . . . . . 11
⊢ 𝑍 =
(ℤ≥‘𝑀) | 
| 9 | 7, 8 | eleq2s 2291 | 
. . . . . . . . . 10
⊢ (𝑗 ∈ 𝑍 → 𝑗 ∈ ℤ) | 
| 10 |   | uzid 9615 | 
. . . . . . . . . 10
⊢ (𝑗 ∈ ℤ → 𝑗 ∈
(ℤ≥‘𝑗)) | 
| 11 | 9, 10 | syl 14 | 
. . . . . . . . 9
⊢ (𝑗 ∈ 𝑍 → 𝑗 ∈ (ℤ≥‘𝑗)) | 
| 12 |   | simpl 109 | 
. . . . . . . . . 10
⊢ (((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → (𝐹‘𝑘) ∈ ℂ) | 
| 13 | 12 | ralimi 2560 | 
. . . . . . . . 9
⊢
(∀𝑘 ∈
(ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → ∀𝑘 ∈ (ℤ≥‘𝑗)(𝐹‘𝑘) ∈ ℂ) | 
| 14 |   | fveq2 5558 | 
. . . . . . . . . . 11
⊢ (𝑘 = 𝑗 → (𝐹‘𝑘) = (𝐹‘𝑗)) | 
| 15 | 14 | eleq1d 2265 | 
. . . . . . . . . 10
⊢ (𝑘 = 𝑗 → ((𝐹‘𝑘) ∈ ℂ ↔ (𝐹‘𝑗) ∈ ℂ)) | 
| 16 | 15 | rspcva 2866 | 
. . . . . . . . 9
⊢ ((𝑗 ∈
(ℤ≥‘𝑗) ∧ ∀𝑘 ∈ (ℤ≥‘𝑗)(𝐹‘𝑘) ∈ ℂ) → (𝐹‘𝑗) ∈ ℂ) | 
| 17 | 11, 13, 16 | syl2an 289 | 
. . . . . . . 8
⊢ ((𝑗 ∈ 𝑍 ∧ ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1)) → (𝐹‘𝑗) ∈ ℂ) | 
| 18 |   | abscl 11216 | 
. . . . . . . 8
⊢ ((𝐹‘𝑗) ∈ ℂ → (abs‘(𝐹‘𝑗)) ∈ ℝ) | 
| 19 | 17, 18 | syl 14 | 
. . . . . . 7
⊢ ((𝑗 ∈ 𝑍 ∧ ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1)) → (abs‘(𝐹‘𝑗)) ∈ ℝ) | 
| 20 |   | 1re 8025 | 
. . . . . . 7
⊢ 1 ∈
ℝ | 
| 21 |   | readdcl 8005 | 
. . . . . . 7
⊢
(((abs‘(𝐹‘𝑗)) ∈ ℝ ∧ 1 ∈ ℝ)
→ ((abs‘(𝐹‘𝑗)) + 1) ∈ ℝ) | 
| 22 | 19, 20, 21 | sylancl 413 | 
. . . . . 6
⊢ ((𝑗 ∈ 𝑍 ∧ ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1)) → ((abs‘(𝐹‘𝑗)) + 1) ∈ ℝ) | 
| 23 |   | simpr 110 | 
. . . . . . . . . . . . 13
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → (𝐹‘𝑘) ∈ ℂ) | 
| 24 |   | simplr 528 | 
. . . . . . . . . . . . 13
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → (𝐹‘𝑗) ∈ ℂ) | 
| 25 |   | abs2dif 11271 | 
. . . . . . . . . . . . 13
⊢ (((𝐹‘𝑘) ∈ ℂ ∧ (𝐹‘𝑗) ∈ ℂ) → ((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) ≤ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗)))) | 
| 26 | 23, 24, 25 | syl2anc 411 | 
. . . . . . . . . . . 12
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → ((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) ≤ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗)))) | 
| 27 |   | abscl 11216 | 
. . . . . . . . . . . . . . 15
⊢ ((𝐹‘𝑘) ∈ ℂ → (abs‘(𝐹‘𝑘)) ∈ ℝ) | 
| 28 | 23, 27 | syl 14 | 
. . . . . . . . . . . . . 14
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → (abs‘(𝐹‘𝑘)) ∈ ℝ) | 
| 29 | 24, 18 | syl 14 | 
. . . . . . . . . . . . . 14
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → (abs‘(𝐹‘𝑗)) ∈ ℝ) | 
| 30 | 28, 29 | resubcld 8407 | 
. . . . . . . . . . . . 13
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → ((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) ∈ ℝ) | 
| 31 | 23, 24 | subcld 8337 | 
. . . . . . . . . . . . . 14
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → ((𝐹‘𝑘) − (𝐹‘𝑗)) ∈ ℂ) | 
| 32 |   | abscl 11216 | 
. . . . . . . . . . . . . 14
⊢ (((𝐹‘𝑘) − (𝐹‘𝑗)) ∈ ℂ → (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) ∈ ℝ) | 
| 33 | 31, 32 | syl 14 | 
. . . . . . . . . . . . 13
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) ∈ ℝ) | 
| 34 |   | lelttr 8115 | 
. . . . . . . . . . . . . 14
⊢
((((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) ∈ ℝ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) ∈ ℝ ∧ 1 ∈ ℝ)
→ ((((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) ≤ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → ((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) < 1)) | 
| 35 | 20, 34 | mp3an3 1337 | 
. . . . . . . . . . . . 13
⊢
((((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) ∈ ℝ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) ∈ ℝ) →
((((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) ≤ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → ((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) < 1)) | 
| 36 | 30, 33, 35 | syl2anc 411 | 
. . . . . . . . . . . 12
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → ((((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) ≤ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → ((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) < 1)) | 
| 37 | 26, 36 | mpand 429 | 
. . . . . . . . . . 11
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → ((abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1 → ((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) < 1)) | 
| 38 |   | ltsubadd2 8460 | 
. . . . . . . . . . . . 13
⊢
(((abs‘(𝐹‘𝑘)) ∈ ℝ ∧ (abs‘(𝐹‘𝑗)) ∈ ℝ ∧ 1 ∈ ℝ)
→ (((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) < 1 ↔ (abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 39 | 20, 38 | mp3an3 1337 | 
. . . . . . . . . . . 12
⊢
(((abs‘(𝐹‘𝑘)) ∈ ℝ ∧ (abs‘(𝐹‘𝑗)) ∈ ℝ) → (((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) < 1 ↔ (abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 40 | 28, 29, 39 | syl2anc 411 | 
. . . . . . . . . . 11
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → (((abs‘(𝐹‘𝑘)) − (abs‘(𝐹‘𝑗))) < 1 ↔ (abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 41 | 37, 40 | sylibd 149 | 
. . . . . . . . . 10
⊢ (((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) ∧ (𝐹‘𝑘) ∈ ℂ) → ((abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1 → (abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 42 | 41 | expimpd 363 | 
. . . . . . . . 9
⊢ ((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) → (((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → (abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 43 | 42 | ralimdv 2565 | 
. . . . . . . 8
⊢ ((𝑗 ∈ 𝑍 ∧ (𝐹‘𝑗) ∈ ℂ) → (∀𝑘 ∈
(ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 44 | 43 | impancom 260 | 
. . . . . . 7
⊢ ((𝑗 ∈ 𝑍 ∧ ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1)) → ((𝐹‘𝑗) ∈ ℂ → ∀𝑘 ∈
(ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 45 | 17, 44 | mpd 13 | 
. . . . . 6
⊢ ((𝑗 ∈ 𝑍 ∧ ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1)) → ∀𝑘 ∈
(ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1)) | 
| 46 |   | breq2 4037 | 
. . . . . . . 8
⊢ (𝑦 = ((abs‘(𝐹‘𝑗)) + 1) → ((abs‘(𝐹‘𝑘)) < 𝑦 ↔ (abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 47 | 46 | ralbidv 2497 | 
. . . . . . 7
⊢ (𝑦 = ((abs‘(𝐹‘𝑗)) + 1) → (∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦 ↔ ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1))) | 
| 48 | 47 | rspcev 2868 | 
. . . . . 6
⊢
((((abs‘(𝐹‘𝑗)) + 1) ∈ ℝ ∧ ∀𝑘 ∈
(ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < ((abs‘(𝐹‘𝑗)) + 1)) → ∃𝑦 ∈ ℝ ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦) | 
| 49 | 22, 45, 48 | syl2anc 411 | 
. . . . 5
⊢ ((𝑗 ∈ 𝑍 ∧ ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1)) → ∃𝑦 ∈ ℝ ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦) | 
| 50 | 49 | ex 115 | 
. . . 4
⊢ (𝑗 ∈ 𝑍 → (∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → ∃𝑦 ∈ ℝ ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦)) | 
| 51 | 50 | reximia 2592 | 
. . 3
⊢
(∃𝑗 ∈
𝑍 ∀𝑘 ∈
(ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → ∃𝑗 ∈ 𝑍 ∃𝑦 ∈ ℝ ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦) | 
| 52 |   | rexcom 2661 | 
. . 3
⊢
(∃𝑗 ∈
𝑍 ∃𝑦 ∈ ℝ ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦 ↔ ∃𝑦 ∈ ℝ ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦) | 
| 53 | 51, 52 | sylib 122 | 
. 2
⊢
(∃𝑗 ∈
𝑍 ∀𝑘 ∈
(ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 1) → ∃𝑦 ∈ ℝ ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦) | 
| 54 | 6, 53 | syl 14 | 
1
⊢
(∀𝑥 ∈
ℝ+ ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)((𝐹‘𝑘) ∈ ℂ ∧ (abs‘((𝐹‘𝑘) − (𝐹‘𝑗))) < 𝑥) → ∃𝑦 ∈ ℝ ∃𝑗 ∈ 𝑍 ∀𝑘 ∈ (ℤ≥‘𝑗)(abs‘(𝐹‘𝑘)) < 𝑦) |