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Mirrors > Home > ILE Home > Th. List > fldiv4lem1div2 | GIF version |
Description: The floor of a positive integer divided by 4 is less than or equal to the half of the integer minus 1. (Contributed by AV, 9-Jul-2021.) |
Ref | Expression |
---|---|
fldiv4lem1div2 | ⊢ (𝑁 ∈ ℕ → (⌊‘(𝑁 / 4)) ≤ ((𝑁 − 1) / 2)) |
Step | Hyp | Ref | Expression |
---|---|---|---|
1 | elnn1uz2 9658 | . 2 ⊢ (𝑁 ∈ ℕ ↔ (𝑁 = 1 ∨ 𝑁 ∈ (ℤ≥‘2))) | |
2 | 1lt4 9142 | . . . . . 6 ⊢ 1 < 4 | |
3 | 1nn0 9242 | . . . . . . 7 ⊢ 1 ∈ ℕ0 | |
4 | 4nn 9131 | . . . . . . 7 ⊢ 4 ∈ ℕ | |
5 | divfl0 10351 | . . . . . . 7 ⊢ ((1 ∈ ℕ0 ∧ 4 ∈ ℕ) → (1 < 4 ↔ (⌊‘(1 / 4)) = 0)) | |
6 | 3, 4, 5 | mp2an 426 | . . . . . 6 ⊢ (1 < 4 ↔ (⌊‘(1 / 4)) = 0) |
7 | 2, 6 | mpbi 145 | . . . . 5 ⊢ (⌊‘(1 / 4)) = 0 |
8 | 1z 9329 | . . . . . . . . 9 ⊢ 1 ∈ ℤ | |
9 | znq 9675 | . . . . . . . . 9 ⊢ ((1 ∈ ℤ ∧ 4 ∈ ℕ) → (1 / 4) ∈ ℚ) | |
10 | 8, 4, 9 | mp2an 426 | . . . . . . . 8 ⊢ (1 / 4) ∈ ℚ |
11 | flqcl 10328 | . . . . . . . 8 ⊢ ((1 / 4) ∈ ℚ → (⌊‘(1 / 4)) ∈ ℤ) | |
12 | 10, 11 | ax-mp 5 | . . . . . . 7 ⊢ (⌊‘(1 / 4)) ∈ ℤ |
13 | 12 | zrei 9309 | . . . . . 6 ⊢ (⌊‘(1 / 4)) ∈ ℝ |
14 | 13 | eqlei 8099 | . . . . 5 ⊢ ((⌊‘(1 / 4)) = 0 → (⌊‘(1 / 4)) ≤ 0) |
15 | 7, 14 | mp1i 10 | . . . 4 ⊢ (𝑁 = 1 → (⌊‘(1 / 4)) ≤ 0) |
16 | fvoveq1 5929 | . . . 4 ⊢ (𝑁 = 1 → (⌊‘(𝑁 / 4)) = (⌊‘(1 / 4))) | |
17 | oveq1 5913 | . . . . . . 7 ⊢ (𝑁 = 1 → (𝑁 − 1) = (1 − 1)) | |
18 | 1m1e0 9037 | . . . . . . 7 ⊢ (1 − 1) = 0 | |
19 | 17, 18 | eqtrdi 2238 | . . . . . 6 ⊢ (𝑁 = 1 → (𝑁 − 1) = 0) |
20 | 19 | oveq1d 5921 | . . . . 5 ⊢ (𝑁 = 1 → ((𝑁 − 1) / 2) = (0 / 2)) |
21 | 2cn 9039 | . . . . . 6 ⊢ 2 ∈ ℂ | |
22 | 2ap0 9061 | . . . . . 6 ⊢ 2 # 0 | |
23 | 21, 22 | div0api 8751 | . . . . 5 ⊢ (0 / 2) = 0 |
24 | 20, 23 | eqtrdi 2238 | . . . 4 ⊢ (𝑁 = 1 → ((𝑁 − 1) / 2) = 0) |
25 | 15, 16, 24 | 3brtr4d 4057 | . . 3 ⊢ (𝑁 = 1 → (⌊‘(𝑁 / 4)) ≤ ((𝑁 − 1) / 2)) |
26 | fldiv4lem1div2uz2 10361 | . . 3 ⊢ (𝑁 ∈ (ℤ≥‘2) → (⌊‘(𝑁 / 4)) ≤ ((𝑁 − 1) / 2)) | |
27 | 25, 26 | jaoi 717 | . 2 ⊢ ((𝑁 = 1 ∨ 𝑁 ∈ (ℤ≥‘2)) → (⌊‘(𝑁 / 4)) ≤ ((𝑁 − 1) / 2)) |
28 | 1, 27 | sylbi 121 | 1 ⊢ (𝑁 ∈ ℕ → (⌊‘(𝑁 / 4)) ≤ ((𝑁 − 1) / 2)) |
Colors of variables: wff set class |
Syntax hints: → wi 4 ↔ wb 105 ∨ wo 709 = wceq 1364 ∈ wcel 2160 class class class wbr 4025 ‘cfv 5242 (class class class)co 5906 0cc0 7858 1c1 7859 < clt 8040 ≤ cle 8041 − cmin 8176 / cdiv 8677 ℕcn 8968 2c2 9019 4c4 9021 ℕ0cn0 9226 ℤcz 9303 ℤ≥cuz 9578 ℚcq 9670 ⌊cfl 10323 |
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 2162 ax-14 2163 ax-ext 2171 ax-sep 4143 ax-pow 4199 ax-pr 4234 ax-un 4458 ax-setind 4561 ax-cnex 7949 ax-resscn 7950 ax-1cn 7951 ax-1re 7952 ax-icn 7953 ax-addcl 7954 ax-addrcl 7955 ax-mulcl 7956 ax-mulrcl 7957 ax-addcom 7958 ax-mulcom 7959 ax-addass 7960 ax-mulass 7961 ax-distr 7962 ax-i2m1 7963 ax-0lt1 7964 ax-1rid 7965 ax-0id 7966 ax-rnegex 7967 ax-precex 7968 ax-cnre 7969 ax-pre-ltirr 7970 ax-pre-ltwlin 7971 ax-pre-lttrn 7972 ax-pre-apti 7973 ax-pre-ltadd 7974 ax-pre-mulgt0 7975 ax-pre-mulext 7976 ax-arch 7977 |
This theorem depends on definitions: df-bi 117 df-dc 836 df-3or 981 df-3an 982 df-tru 1367 df-fal 1370 df-nf 1472 df-sb 1774 df-eu 2041 df-mo 2042 df-clab 2176 df-cleq 2182 df-clel 2185 df-nfc 2321 df-ne 2361 df-nel 2456 df-ral 2473 df-rex 2474 df-reu 2475 df-rmo 2476 df-rab 2477 df-v 2758 df-sbc 2982 df-csb 3077 df-dif 3151 df-un 3153 df-in 3155 df-ss 3162 df-pw 3599 df-sn 3620 df-pr 3621 df-op 3623 df-uni 3832 df-int 3867 df-iun 3910 df-br 4026 df-opab 4087 df-mpt 4088 df-id 4318 df-po 4321 df-iso 4322 df-xp 4657 df-rel 4658 df-cnv 4659 df-co 4660 df-dm 4661 df-rn 4662 df-res 4663 df-ima 4664 df-iota 5203 df-fun 5244 df-fn 5245 df-f 5246 df-fv 5250 df-riota 5861 df-ov 5909 df-oprab 5910 df-mpo 5911 df-1st 6180 df-2nd 6181 df-pnf 8042 df-mnf 8043 df-xr 8044 df-ltxr 8045 df-le 8046 df-sub 8178 df-neg 8179 df-reap 8580 df-ap 8587 df-div 8678 df-inn 8969 df-2 9027 df-3 9028 df-4 9029 df-n0 9227 df-z 9304 df-uz 9579 df-q 9671 df-rp 9706 df-fl 10325 |
This theorem is referenced by: gausslemma2dlem0g 15099 |
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