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Mirrors > Home > ILE Home > Th. List > fldiv4lem1div2uz2 | GIF version |
Description: The floor of an integer greater than 1, divided by 4 is less than or equal to the half of the integer minus 1. (Contributed by AV, 5-Jul-2021.) (Proof shortened by AV, 9-Jul-2022.) |
Ref | Expression |
---|---|
fldiv4lem1div2uz2 | ⊢ (𝑁 ∈ (ℤ≥‘2) → (⌊‘(𝑁 / 4)) ≤ ((𝑁 − 1) / 2)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | eluzelz 9591 | . . . . 5 ⊢ (𝑁 ∈ (ℤ≥‘2) → 𝑁 ∈ ℤ) | |
2 | 4nn 9135 | . . . . 5 ⊢ 4 ∈ ℕ | |
3 | znq 9679 | . . . . 5 ⊢ ((𝑁 ∈ ℤ ∧ 4 ∈ ℕ) → (𝑁 / 4) ∈ ℚ) | |
4 | 1, 2, 3 | sylancl 413 | . . . 4 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 / 4) ∈ ℚ) |
5 | 4 | flqcld 10336 | . . 3 ⊢ (𝑁 ∈ (ℤ≥‘2) → (⌊‘(𝑁 / 4)) ∈ ℤ) |
6 | 5 | zred 9429 | . 2 ⊢ (𝑁 ∈ (ℤ≥‘2) → (⌊‘(𝑁 / 4)) ∈ ℝ) |
7 | eluzelre 9592 | . . 3 ⊢ (𝑁 ∈ (ℤ≥‘2) → 𝑁 ∈ ℝ) | |
8 | 2 | a1i 9 | . . 3 ⊢ (𝑁 ∈ (ℤ≥‘2) → 4 ∈ ℕ) |
9 | 7, 8 | nndivred 9022 | . 2 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 / 4) ∈ ℝ) |
10 | peano2rem 8276 | . . . 4 ⊢ (𝑁 ∈ ℝ → (𝑁 − 1) ∈ ℝ) | |
11 | 7, 10 | syl 14 | . . 3 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 − 1) ∈ ℝ) |
12 | 11 | rehalfcld 9219 | . 2 ⊢ (𝑁 ∈ (ℤ≥‘2) → ((𝑁 − 1) / 2) ∈ ℝ) |
13 | flqle 10337 | . . 3 ⊢ ((𝑁 / 4) ∈ ℚ → (⌊‘(𝑁 / 4)) ≤ (𝑁 / 4)) | |
14 | 4, 13 | syl 14 | . 2 ⊢ (𝑁 ∈ (ℤ≥‘2) → (⌊‘(𝑁 / 4)) ≤ (𝑁 / 4)) |
15 | 1red 8024 | . . . 4 ⊢ (𝑁 ∈ (ℤ≥‘2) → 1 ∈ ℝ) | |
16 | zre 9311 | . . . . 5 ⊢ (𝑁 ∈ ℤ → 𝑁 ∈ ℝ) | |
17 | rehalfcl 9199 | . . . . 5 ⊢ (𝑁 ∈ ℝ → (𝑁 / 2) ∈ ℝ) | |
18 | 1, 16, 17 | 3syl 17 | . . . 4 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 / 2) ∈ ℝ) |
19 | 2rp 9714 | . . . . . 6 ⊢ 2 ∈ ℝ+ | |
20 | eluzle 9594 | . . . . . 6 ⊢ (𝑁 ∈ (ℤ≥‘2) → 2 ≤ 𝑁) | |
21 | divge1 9779 | . . . . . 6 ⊢ ((2 ∈ ℝ+ ∧ 𝑁 ∈ ℝ ∧ 2 ≤ 𝑁) → 1 ≤ (𝑁 / 2)) | |
22 | 19, 7, 20, 21 | mp3an2i 1353 | . . . . 5 ⊢ (𝑁 ∈ (ℤ≥‘2) → 1 ≤ (𝑁 / 2)) |
23 | eluzelcn 9593 | . . . . . 6 ⊢ (𝑁 ∈ (ℤ≥‘2) → 𝑁 ∈ ℂ) | |
24 | subhalfhalf 9207 | . . . . . 6 ⊢ (𝑁 ∈ ℂ → (𝑁 − (𝑁 / 2)) = (𝑁 / 2)) | |
25 | 23, 24 | syl 14 | . . . . 5 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 − (𝑁 / 2)) = (𝑁 / 2)) |
26 | 22, 25 | breqtrrd 4057 | . . . 4 ⊢ (𝑁 ∈ (ℤ≥‘2) → 1 ≤ (𝑁 − (𝑁 / 2))) |
27 | 15, 7, 18, 26 | lesubd 8558 | . . 3 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 / 2) ≤ (𝑁 − 1)) |
28 | 2t2e4 9126 | . . . . . . . . 9 ⊢ (2 · 2) = 4 | |
29 | 28 | eqcomi 2197 | . . . . . . . 8 ⊢ 4 = (2 · 2) |
30 | 29 | a1i 9 | . . . . . . 7 ⊢ (𝑁 ∈ (ℤ≥‘2) → 4 = (2 · 2)) |
31 | 30 | oveq2d 5926 | . . . . . 6 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 / 4) = (𝑁 / (2 · 2))) |
32 | 2cnd 9045 | . . . . . . 7 ⊢ (𝑁 ∈ (ℤ≥‘2) → 2 ∈ ℂ) | |
33 | 19 | a1i 9 | . . . . . . . 8 ⊢ (𝑁 ∈ (ℤ≥‘2) → 2 ∈ ℝ+) |
34 | 33 | rpap0d 9758 | . . . . . . 7 ⊢ (𝑁 ∈ (ℤ≥‘2) → 2 # 0) |
35 | 23, 32, 32, 34, 34 | divdivap1d 8831 | . . . . . 6 ⊢ (𝑁 ∈ (ℤ≥‘2) → ((𝑁 / 2) / 2) = (𝑁 / (2 · 2))) |
36 | 31, 35 | eqtr4d 2229 | . . . . 5 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 / 4) = ((𝑁 / 2) / 2)) |
37 | 36 | breq1d 4039 | . . . 4 ⊢ (𝑁 ∈ (ℤ≥‘2) → ((𝑁 / 4) ≤ ((𝑁 − 1) / 2) ↔ ((𝑁 / 2) / 2) ≤ ((𝑁 − 1) / 2))) |
38 | 18, 11, 33 | lediv1d 9799 | . . . 4 ⊢ (𝑁 ∈ (ℤ≥‘2) → ((𝑁 / 2) ≤ (𝑁 − 1) ↔ ((𝑁 / 2) / 2) ≤ ((𝑁 − 1) / 2))) |
39 | 37, 38 | bitr4d 191 | . . 3 ⊢ (𝑁 ∈ (ℤ≥‘2) → ((𝑁 / 4) ≤ ((𝑁 − 1) / 2) ↔ (𝑁 / 2) ≤ (𝑁 − 1))) |
40 | 27, 39 | mpbird 167 | . 2 ⊢ (𝑁 ∈ (ℤ≥‘2) → (𝑁 / 4) ≤ ((𝑁 − 1) / 2)) |
41 | 6, 9, 12, 14, 40 | letrd 8133 | 1 ⊢ (𝑁 ∈ (ℤ≥‘2) → (⌊‘(𝑁 / 4)) ≤ ((𝑁 − 1) / 2)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 = wceq 1364 ∈ wcel 2164 class class class wbr 4029 ‘cfv 5246 (class class class)co 5910 ℂcc 7860 ℝcr 7861 1c1 7863 · cmul 7867 ≤ cle 8045 − cmin 8180 / cdiv 8681 ℕcn 8972 2c2 9023 4c4 9025 ℤcz 9307 ℤ≥cuz 9582 ℚcq 9674 ℝ+crp 9709 ⌊cfl 10327 |
This theorem was proved from axioms: ax-mp 5 ax-1 6 ax-2 7 ax-ia1 106 ax-ia2 107 ax-ia3 108 ax-in1 615 ax-in2 616 ax-io 710 ax-5 1458 ax-7 1459 ax-gen 1460 ax-ie1 1504 ax-ie2 1505 ax-8 1515 ax-10 1516 ax-11 1517 ax-i12 1518 ax-bndl 1520 ax-4 1521 ax-17 1537 ax-i9 1541 ax-ial 1545 ax-i5r 1546 ax-13 2166 ax-14 2167 ax-ext 2175 ax-sep 4147 ax-pow 4203 ax-pr 4238 ax-un 4462 ax-setind 4565 ax-cnex 7953 ax-resscn 7954 ax-1cn 7955 ax-1re 7956 ax-icn 7957 ax-addcl 7958 ax-addrcl 7959 ax-mulcl 7960 ax-mulrcl 7961 ax-addcom 7962 ax-mulcom 7963 ax-addass 7964 ax-mulass 7965 ax-distr 7966 ax-i2m1 7967 ax-0lt1 7968 ax-1rid 7969 ax-0id 7970 ax-rnegex 7971 ax-precex 7972 ax-cnre 7973 ax-pre-ltirr 7974 ax-pre-ltwlin 7975 ax-pre-lttrn 7976 ax-pre-apti 7977 ax-pre-ltadd 7978 ax-pre-mulgt0 7979 ax-pre-mulext 7980 ax-arch 7981 |
This theorem depends on definitions: df-bi 117 df-3or 981 df-3an 982 df-tru 1367 df-fal 1370 df-nf 1472 df-sb 1774 df-eu 2045 df-mo 2046 df-clab 2180 df-cleq 2186 df-clel 2189 df-nfc 2325 df-ne 2365 df-nel 2460 df-ral 2477 df-rex 2478 df-reu 2479 df-rmo 2480 df-rab 2481 df-v 2762 df-sbc 2986 df-csb 3081 df-dif 3155 df-un 3157 df-in 3159 df-ss 3166 df-pw 3603 df-sn 3624 df-pr 3625 df-op 3627 df-uni 3836 df-int 3871 df-iun 3914 df-br 4030 df-opab 4091 df-mpt 4092 df-id 4322 df-po 4325 df-iso 4326 df-xp 4661 df-rel 4662 df-cnv 4663 df-co 4664 df-dm 4665 df-rn 4666 df-res 4667 df-ima 4668 df-iota 5207 df-fun 5248 df-fn 5249 df-f 5250 df-fv 5254 df-riota 5865 df-ov 5913 df-oprab 5914 df-mpo 5915 df-1st 6184 df-2nd 6185 df-pnf 8046 df-mnf 8047 df-xr 8048 df-ltxr 8049 df-le 8050 df-sub 8182 df-neg 8183 df-reap 8584 df-ap 8591 df-div 8682 df-inn 8973 df-2 9031 df-3 9032 df-4 9033 df-n0 9231 df-z 9308 df-uz 9583 df-q 9675 df-rp 9710 df-fl 10329 |
This theorem is referenced by: fldiv4lem1div2 10366 gausslemma2dlem4 15122 |
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