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Mirrors > Home > MPE Home > Th. List > flval3 | Structured version Visualization version GIF version |
Description: An alternate way to define the floor function, as the supremum of all integers less than or equal to its argument. (Contributed by NM, 15-Nov-2004.) (Proof shortened by Mario Carneiro, 6-Sep-2014.) |
Ref | Expression |
---|---|
flval3 | ⊢ (𝐴 ∈ ℝ → (⌊‘𝐴) = sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < )) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | ssrab2 4070 | . . . . 5 ⊢ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴} ⊆ ℤ | |
2 | zssre 12564 | . . . . 5 ⊢ ℤ ⊆ ℝ | |
3 | 1, 2 | sstri 3984 | . . . 4 ⊢ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴} ⊆ ℝ |
4 | 3 | a1i 11 | . . 3 ⊢ (𝐴 ∈ ℝ → {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴} ⊆ ℝ) |
5 | breq1 5142 | . . . . 5 ⊢ (𝑥 = (⌊‘𝐴) → (𝑥 ≤ 𝐴 ↔ (⌊‘𝐴) ≤ 𝐴)) | |
6 | flcl 13761 | . . . . 5 ⊢ (𝐴 ∈ ℝ → (⌊‘𝐴) ∈ ℤ) | |
7 | flle 13765 | . . . . 5 ⊢ (𝐴 ∈ ℝ → (⌊‘𝐴) ≤ 𝐴) | |
8 | 5, 6, 7 | elrabd 3678 | . . . 4 ⊢ (𝐴 ∈ ℝ → (⌊‘𝐴) ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}) |
9 | 8 | ne0d 4328 | . . 3 ⊢ (𝐴 ∈ ℝ → {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴} ≠ ∅) |
10 | reflcl 13762 | . . . 4 ⊢ (𝐴 ∈ ℝ → (⌊‘𝐴) ∈ ℝ) | |
11 | breq1 5142 | . . . . . . 7 ⊢ (𝑥 = 𝑧 → (𝑥 ≤ 𝐴 ↔ 𝑧 ≤ 𝐴)) | |
12 | 11 | elrab 3676 | . . . . . 6 ⊢ (𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴} ↔ (𝑧 ∈ ℤ ∧ 𝑧 ≤ 𝐴)) |
13 | flge 13771 | . . . . . . . 8 ⊢ ((𝐴 ∈ ℝ ∧ 𝑧 ∈ ℤ) → (𝑧 ≤ 𝐴 ↔ 𝑧 ≤ (⌊‘𝐴))) | |
14 | 13 | biimpd 228 | . . . . . . 7 ⊢ ((𝐴 ∈ ℝ ∧ 𝑧 ∈ ℤ) → (𝑧 ≤ 𝐴 → 𝑧 ≤ (⌊‘𝐴))) |
15 | 14 | expimpd 453 | . . . . . 6 ⊢ (𝐴 ∈ ℝ → ((𝑧 ∈ ℤ ∧ 𝑧 ≤ 𝐴) → 𝑧 ≤ (⌊‘𝐴))) |
16 | 12, 15 | biimtrid 241 | . . . . 5 ⊢ (𝐴 ∈ ℝ → (𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴} → 𝑧 ≤ (⌊‘𝐴))) |
17 | 16 | ralrimiv 3137 | . . . 4 ⊢ (𝐴 ∈ ℝ → ∀𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}𝑧 ≤ (⌊‘𝐴)) |
18 | brralrspcev 5199 | . . . 4 ⊢ (((⌊‘𝐴) ∈ ℝ ∧ ∀𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}𝑧 ≤ (⌊‘𝐴)) → ∃𝑦 ∈ ℝ ∀𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}𝑧 ≤ 𝑦) | |
19 | 10, 17, 18 | syl2anc 583 | . . 3 ⊢ (𝐴 ∈ ℝ → ∃𝑦 ∈ ℝ ∀𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}𝑧 ≤ 𝑦) |
20 | 4, 9, 19, 8 | suprubd 12175 | . 2 ⊢ (𝐴 ∈ ℝ → (⌊‘𝐴) ≤ sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < )) |
21 | suprleub 12179 | . . . 4 ⊢ ((({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴} ⊆ ℝ ∧ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴} ≠ ∅ ∧ ∃𝑦 ∈ ℝ ∀𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}𝑧 ≤ 𝑦) ∧ (⌊‘𝐴) ∈ ℝ) → (sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < ) ≤ (⌊‘𝐴) ↔ ∀𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}𝑧 ≤ (⌊‘𝐴))) | |
22 | 4, 9, 19, 10, 21 | syl31anc 1370 | . . 3 ⊢ (𝐴 ∈ ℝ → (sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < ) ≤ (⌊‘𝐴) ↔ ∀𝑧 ∈ {𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}𝑧 ≤ (⌊‘𝐴))) |
23 | 17, 22 | mpbird 257 | . 2 ⊢ (𝐴 ∈ ℝ → sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < ) ≤ (⌊‘𝐴)) |
24 | 4, 9, 19 | suprcld 12176 | . . 3 ⊢ (𝐴 ∈ ℝ → sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < ) ∈ ℝ) |
25 | 10, 24 | letri3d 11355 | . 2 ⊢ (𝐴 ∈ ℝ → ((⌊‘𝐴) = sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < ) ↔ ((⌊‘𝐴) ≤ sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < ) ∧ sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < ) ≤ (⌊‘𝐴)))) |
26 | 20, 23, 25 | mpbir2and 710 | 1 ⊢ (𝐴 ∈ ℝ → (⌊‘𝐴) = sup({𝑥 ∈ ℤ ∣ 𝑥 ≤ 𝐴}, ℝ, < )) |
Colors of variables: wff setvar class |
Syntax hints: → wi 4 ↔ wb 205 ∧ wa 395 = wceq 1533 ∈ wcel 2098 ≠ wne 2932 ∀wral 3053 ∃wrex 3062 {crab 3424 ⊆ wss 3941 ∅c0 4315 class class class wbr 5139 ‘cfv 6534 supcsup 9432 ℝcr 11106 < clt 11247 ≤ cle 11248 ℤcz 12557 ⌊cfl 13756 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-3 8 ax-gen 1789 ax-4 1803 ax-5 1905 ax-6 1963 ax-7 2003 ax-8 2100 ax-9 2108 ax-10 2129 ax-11 2146 ax-12 2163 ax-ext 2695 ax-sep 5290 ax-nul 5297 ax-pow 5354 ax-pr 5418 ax-un 7719 ax-cnex 11163 ax-resscn 11164 ax-1cn 11165 ax-icn 11166 ax-addcl 11167 ax-addrcl 11168 ax-mulcl 11169 ax-mulrcl 11170 ax-mulcom 11171 ax-addass 11172 ax-mulass 11173 ax-distr 11174 ax-i2m1 11175 ax-1ne0 11176 ax-1rid 11177 ax-rnegex 11178 ax-rrecex 11179 ax-cnre 11180 ax-pre-lttri 11181 ax-pre-lttrn 11182 ax-pre-ltadd 11183 ax-pre-mulgt0 11184 ax-pre-sup 11185 |
This theorem depends on definitions: df-bi 206 df-an 396 df-or 845 df-3or 1085 df-3an 1086 df-tru 1536 df-fal 1546 df-ex 1774 df-nf 1778 df-sb 2060 df-mo 2526 df-eu 2555 df-clab 2702 df-cleq 2716 df-clel 2802 df-nfc 2877 df-ne 2933 df-nel 3039 df-ral 3054 df-rex 3063 df-rmo 3368 df-reu 3369 df-rab 3425 df-v 3468 df-sbc 3771 df-csb 3887 df-dif 3944 df-un 3946 df-in 3948 df-ss 3958 df-pss 3960 df-nul 4316 df-if 4522 df-pw 4597 df-sn 4622 df-pr 4624 df-op 4628 df-uni 4901 df-iun 4990 df-br 5140 df-opab 5202 df-mpt 5223 df-tr 5257 df-id 5565 df-eprel 5571 df-po 5579 df-so 5580 df-fr 5622 df-we 5624 df-xp 5673 df-rel 5674 df-cnv 5675 df-co 5676 df-dm 5677 df-rn 5678 df-res 5679 df-ima 5680 df-pred 6291 df-ord 6358 df-on 6359 df-lim 6360 df-suc 6361 df-iota 6486 df-fun 6536 df-fn 6537 df-f 6538 df-f1 6539 df-fo 6540 df-f1o 6541 df-fv 6542 df-riota 7358 df-ov 7405 df-oprab 7406 df-mpo 7407 df-om 7850 df-2nd 7970 df-frecs 8262 df-wrecs 8293 df-recs 8367 df-rdg 8406 df-er 8700 df-en 8937 df-dom 8938 df-sdom 8939 df-sup 9434 df-inf 9435 df-pnf 11249 df-mnf 11250 df-xr 11251 df-ltxr 11252 df-le 11253 df-sub 11445 df-neg 11446 df-nn 12212 df-n0 12472 df-z 12558 df-uz 12822 df-fl 13758 |
This theorem is referenced by: (None) |
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