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Theorem 4sqlem19 17010
Description: Lemma for 4sq 17011. The proof is by strong induction - we show that if all the integers less than 𝑘 are in 𝑆, then 𝑘 is as well. In this part of the proof we do the induction argument and dispense with all the cases except the odd prime case, which is sent to 4sqlem18 17009. If 𝑘 is 0, 1, 2, we show 𝑘𝑆 directly; otherwise if 𝑘 is composite, 𝑘 is the product of two numbers less than it (and hence in 𝑆 by assumption), so by mul4sq 17001 𝑘𝑆. (Contributed by Mario Carneiro, 14-Jul-2014.) (Revised by Mario Carneiro, 20-Jun-2015.)
Hypothesis
Ref Expression
4sq.1 𝑆 = {𝑛 ∣ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ ∃𝑧 ∈ ℤ ∃𝑤 ∈ ℤ 𝑛 = (((𝑥↑2) + (𝑦↑2)) + ((𝑧↑2) + (𝑤↑2)))}
Assertion
Ref Expression
4sqlem19 0 = 𝑆
Distinct variable groups:   𝑤,𝑛,𝑥,𝑦,𝑧   𝑆,𝑛
Allowed substitution hints:   𝑆(𝑥,𝑦,𝑧,𝑤)

Proof of Theorem 4sqlem19
Dummy variables 𝑗 𝑘 𝑖 𝑚 are mutually distinct and distinct from all other variables.
StepHypRef Expression
1 elnn0 12555 . . . 4 (𝑘 ∈ ℕ0 ↔ (𝑘 ∈ ℕ ∨ 𝑘 = 0))
2 eleq1 2832 . . . . . 6 (𝑗 = 1 → (𝑗𝑆 ↔ 1 ∈ 𝑆))
3 eleq1 2832 . . . . . 6 (𝑗 = 𝑚 → (𝑗𝑆𝑚𝑆))
4 eleq1 2832 . . . . . 6 (𝑗 = 𝑖 → (𝑗𝑆𝑖𝑆))
5 eleq1 2832 . . . . . 6 (𝑗 = (𝑚 · 𝑖) → (𝑗𝑆 ↔ (𝑚 · 𝑖) ∈ 𝑆))
6 eleq1 2832 . . . . . 6 (𝑗 = 𝑘 → (𝑗𝑆𝑘𝑆))
7 abs1 15346 . . . . . . . . . . 11 (abs‘1) = 1
87oveq1i 7458 . . . . . . . . . 10 ((abs‘1)↑2) = (1↑2)
9 sq1 14244 . . . . . . . . . 10 (1↑2) = 1
108, 9eqtri 2768 . . . . . . . . 9 ((abs‘1)↑2) = 1
11 abs0 15334 . . . . . . . . . . 11 (abs‘0) = 0
1211oveq1i 7458 . . . . . . . . . 10 ((abs‘0)↑2) = (0↑2)
13 sq0 14241 . . . . . . . . . 10 (0↑2) = 0
1412, 13eqtri 2768 . . . . . . . . 9 ((abs‘0)↑2) = 0
1510, 14oveq12i 7460 . . . . . . . 8 (((abs‘1)↑2) + ((abs‘0)↑2)) = (1 + 0)
16 1p0e1 12417 . . . . . . . 8 (1 + 0) = 1
1715, 16eqtri 2768 . . . . . . 7 (((abs‘1)↑2) + ((abs‘0)↑2)) = 1
18 1z 12673 . . . . . . . . 9 1 ∈ ℤ
19 zgz 16980 . . . . . . . . 9 (1 ∈ ℤ → 1 ∈ ℤ[i])
2018, 19ax-mp 5 . . . . . . . 8 1 ∈ ℤ[i]
21 0z 12650 . . . . . . . . 9 0 ∈ ℤ
22 zgz 16980 . . . . . . . . 9 (0 ∈ ℤ → 0 ∈ ℤ[i])
2321, 22ax-mp 5 . . . . . . . 8 0 ∈ ℤ[i]
24 4sq.1 . . . . . . . . 9 𝑆 = {𝑛 ∣ ∃𝑥 ∈ ℤ ∃𝑦 ∈ ℤ ∃𝑧 ∈ ℤ ∃𝑤 ∈ ℤ 𝑛 = (((𝑥↑2) + (𝑦↑2)) + ((𝑧↑2) + (𝑤↑2)))}
25244sqlem4a 16998 . . . . . . . 8 ((1 ∈ ℤ[i] ∧ 0 ∈ ℤ[i]) → (((abs‘1)↑2) + ((abs‘0)↑2)) ∈ 𝑆)
2620, 23, 25mp2an 691 . . . . . . 7 (((abs‘1)↑2) + ((abs‘0)↑2)) ∈ 𝑆
2717, 26eqeltrri 2841 . . . . . 6 1 ∈ 𝑆
28 eleq1 2832 . . . . . . 7 (𝑗 = 2 → (𝑗𝑆 ↔ 2 ∈ 𝑆))
29 eldifsn 4811 . . . . . . . . 9 (𝑗 ∈ (ℙ ∖ {2}) ↔ (𝑗 ∈ ℙ ∧ 𝑗 ≠ 2))
30 oddprm 16857 . . . . . . . . . . 11 (𝑗 ∈ (ℙ ∖ {2}) → ((𝑗 − 1) / 2) ∈ ℕ)
3130adantr 480 . . . . . . . . . 10 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → ((𝑗 − 1) / 2) ∈ ℕ)
32 eldifi 4154 . . . . . . . . . . . . . . . 16 (𝑗 ∈ (ℙ ∖ {2}) → 𝑗 ∈ ℙ)
3332adantr 480 . . . . . . . . . . . . . . 15 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 𝑗 ∈ ℙ)
34 prmnn 16721 . . . . . . . . . . . . . . 15 (𝑗 ∈ ℙ → 𝑗 ∈ ℕ)
35 nncn 12301 . . . . . . . . . . . . . . 15 (𝑗 ∈ ℕ → 𝑗 ∈ ℂ)
3633, 34, 353syl 18 . . . . . . . . . . . . . 14 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 𝑗 ∈ ℂ)
37 ax-1cn 11242 . . . . . . . . . . . . . 14 1 ∈ ℂ
38 subcl 11535 . . . . . . . . . . . . . 14 ((𝑗 ∈ ℂ ∧ 1 ∈ ℂ) → (𝑗 − 1) ∈ ℂ)
3936, 37, 38sylancl 585 . . . . . . . . . . . . 13 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (𝑗 − 1) ∈ ℂ)
40 2cnd 12371 . . . . . . . . . . . . 13 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 2 ∈ ℂ)
41 2ne0 12397 . . . . . . . . . . . . . 14 2 ≠ 0
4241a1i 11 . . . . . . . . . . . . 13 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 2 ≠ 0)
4339, 40, 42divcan2d 12072 . . . . . . . . . . . 12 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (2 · ((𝑗 − 1) / 2)) = (𝑗 − 1))
4443oveq1d 7463 . . . . . . . . . . 11 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → ((2 · ((𝑗 − 1) / 2)) + 1) = ((𝑗 − 1) + 1))
45 npcan 11545 . . . . . . . . . . . 12 ((𝑗 ∈ ℂ ∧ 1 ∈ ℂ) → ((𝑗 − 1) + 1) = 𝑗)
4636, 37, 45sylancl 585 . . . . . . . . . . 11 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → ((𝑗 − 1) + 1) = 𝑗)
4744, 46eqtr2d 2781 . . . . . . . . . 10 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 𝑗 = ((2 · ((𝑗 − 1) / 2)) + 1))
4843oveq2d 7464 . . . . . . . . . . . 12 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (0...(2 · ((𝑗 − 1) / 2))) = (0...(𝑗 − 1)))
49 nnm1nn0 12594 . . . . . . . . . . . . . . 15 (𝑗 ∈ ℕ → (𝑗 − 1) ∈ ℕ0)
5033, 34, 493syl 18 . . . . . . . . . . . . . 14 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (𝑗 − 1) ∈ ℕ0)
51 elnn0uz 12948 . . . . . . . . . . . . . 14 ((𝑗 − 1) ∈ ℕ0 ↔ (𝑗 − 1) ∈ (ℤ‘0))
5250, 51sylib 218 . . . . . . . . . . . . 13 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (𝑗 − 1) ∈ (ℤ‘0))
53 eluzfz1 13591 . . . . . . . . . . . . 13 ((𝑗 − 1) ∈ (ℤ‘0) → 0 ∈ (0...(𝑗 − 1)))
54 fzsplit 13610 . . . . . . . . . . . . 13 (0 ∈ (0...(𝑗 − 1)) → (0...(𝑗 − 1)) = ((0...0) ∪ ((0 + 1)...(𝑗 − 1))))
5552, 53, 543syl 18 . . . . . . . . . . . 12 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (0...(𝑗 − 1)) = ((0...0) ∪ ((0 + 1)...(𝑗 − 1))))
5648, 55eqtrd 2780 . . . . . . . . . . 11 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (0...(2 · ((𝑗 − 1) / 2))) = ((0...0) ∪ ((0 + 1)...(𝑗 − 1))))
57 fz0sn 13684 . . . . . . . . . . . . . 14 (0...0) = {0}
5814, 14oveq12i 7460 . . . . . . . . . . . . . . . . 17 (((abs‘0)↑2) + ((abs‘0)↑2)) = (0 + 0)
59 00id 11465 . . . . . . . . . . . . . . . . 17 (0 + 0) = 0
6058, 59eqtri 2768 . . . . . . . . . . . . . . . 16 (((abs‘0)↑2) + ((abs‘0)↑2)) = 0
61244sqlem4a 16998 . . . . . . . . . . . . . . . . 17 ((0 ∈ ℤ[i] ∧ 0 ∈ ℤ[i]) → (((abs‘0)↑2) + ((abs‘0)↑2)) ∈ 𝑆)
6223, 23, 61mp2an 691 . . . . . . . . . . . . . . . 16 (((abs‘0)↑2) + ((abs‘0)↑2)) ∈ 𝑆
6360, 62eqeltrri 2841 . . . . . . . . . . . . . . 15 0 ∈ 𝑆
64 snssi 4833 . . . . . . . . . . . . . . 15 (0 ∈ 𝑆 → {0} ⊆ 𝑆)
6563, 64ax-mp 5 . . . . . . . . . . . . . 14 {0} ⊆ 𝑆
6657, 65eqsstri 4043 . . . . . . . . . . . . 13 (0...0) ⊆ 𝑆
6766a1i 11 . . . . . . . . . . . 12 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (0...0) ⊆ 𝑆)
68 0p1e1 12415 . . . . . . . . . . . . . 14 (0 + 1) = 1
6968oveq1i 7458 . . . . . . . . . . . . 13 ((0 + 1)...(𝑗 − 1)) = (1...(𝑗 − 1))
70 simpr 484 . . . . . . . . . . . . . 14 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆)
71 dfss3 3997 . . . . . . . . . . . . . 14 ((1...(𝑗 − 1)) ⊆ 𝑆 ↔ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆)
7270, 71sylibr 234 . . . . . . . . . . . . 13 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (1...(𝑗 − 1)) ⊆ 𝑆)
7369, 72eqsstrid 4057 . . . . . . . . . . . 12 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → ((0 + 1)...(𝑗 − 1)) ⊆ 𝑆)
7467, 73unssd 4215 . . . . . . . . . . 11 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → ((0...0) ∪ ((0 + 1)...(𝑗 − 1))) ⊆ 𝑆)
7556, 74eqsstrd 4047 . . . . . . . . . 10 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → (0...(2 · ((𝑗 − 1) / 2))) ⊆ 𝑆)
76 oveq1 7455 . . . . . . . . . . . 12 (𝑘 = 𝑖 → (𝑘 · 𝑗) = (𝑖 · 𝑗))
7776eleq1d 2829 . . . . . . . . . . 11 (𝑘 = 𝑖 → ((𝑘 · 𝑗) ∈ 𝑆 ↔ (𝑖 · 𝑗) ∈ 𝑆))
7877cbvrabv 3454 . . . . . . . . . 10 {𝑘 ∈ ℕ ∣ (𝑘 · 𝑗) ∈ 𝑆} = {𝑖 ∈ ℕ ∣ (𝑖 · 𝑗) ∈ 𝑆}
79 eqid 2740 . . . . . . . . . 10 inf({𝑘 ∈ ℕ ∣ (𝑘 · 𝑗) ∈ 𝑆}, ℝ, < ) = inf({𝑘 ∈ ℕ ∣ (𝑘 · 𝑗) ∈ 𝑆}, ℝ, < )
8024, 31, 47, 33, 75, 78, 794sqlem18 17009 . . . . . . . . 9 ((𝑗 ∈ (ℙ ∖ {2}) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 𝑗𝑆)
8129, 80sylanbr 581 . . . . . . . 8 (((𝑗 ∈ ℙ ∧ 𝑗 ≠ 2) ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 𝑗𝑆)
8281an32s 651 . . . . . . 7 (((𝑗 ∈ ℙ ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) ∧ 𝑗 ≠ 2) → 𝑗𝑆)
8310, 10oveq12i 7460 . . . . . . . . . 10 (((abs‘1)↑2) + ((abs‘1)↑2)) = (1 + 1)
84 df-2 12356 . . . . . . . . . 10 2 = (1 + 1)
8583, 84eqtr4i 2771 . . . . . . . . 9 (((abs‘1)↑2) + ((abs‘1)↑2)) = 2
86244sqlem4a 16998 . . . . . . . . . 10 ((1 ∈ ℤ[i] ∧ 1 ∈ ℤ[i]) → (((abs‘1)↑2) + ((abs‘1)↑2)) ∈ 𝑆)
8720, 20, 86mp2an 691 . . . . . . . . 9 (((abs‘1)↑2) + ((abs‘1)↑2)) ∈ 𝑆
8885, 87eqeltrri 2841 . . . . . . . 8 2 ∈ 𝑆
8988a1i 11 . . . . . . 7 ((𝑗 ∈ ℙ ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 2 ∈ 𝑆)
9028, 82, 89pm2.61ne 3033 . . . . . 6 ((𝑗 ∈ ℙ ∧ ∀𝑚 ∈ (1...(𝑗 − 1))𝑚𝑆) → 𝑗𝑆)
9124mul4sq 17001 . . . . . . 7 ((𝑚𝑆𝑖𝑆) → (𝑚 · 𝑖) ∈ 𝑆)
9291a1i 11 . . . . . 6 ((𝑚 ∈ (ℤ‘2) ∧ 𝑖 ∈ (ℤ‘2)) → ((𝑚𝑆𝑖𝑆) → (𝑚 · 𝑖) ∈ 𝑆))
932, 3, 4, 5, 6, 27, 90, 92prmind2 16732 . . . . 5 (𝑘 ∈ ℕ → 𝑘𝑆)
94 id 22 . . . . . 6 (𝑘 = 0 → 𝑘 = 0)
9594, 63eqeltrdi 2852 . . . . 5 (𝑘 = 0 → 𝑘𝑆)
9693, 95jaoi 856 . . . 4 ((𝑘 ∈ ℕ ∨ 𝑘 = 0) → 𝑘𝑆)
971, 96sylbi 217 . . 3 (𝑘 ∈ ℕ0𝑘𝑆)
9897ssriv 4012 . 2 0𝑆
99244sqlem1 16995 . 2 𝑆 ⊆ ℕ0
10098, 99eqssi 4025 1 0 = 𝑆
Colors of variables: wff setvar class
Syntax hints:  wi 4  wa 395  wo 846   = wceq 1537  wcel 2108  {cab 2717  wne 2946  wral 3067  wrex 3076  {crab 3443  cdif 3973  cun 3974  wss 3976  {csn 4648  cfv 6573  (class class class)co 7448  infcinf 9510  cc 11182  cr 11183  0cc0 11184  1c1 11185   + caddc 11187   · cmul 11189   < clt 11324  cmin 11520   / cdiv 11947  cn 12293  2c2 12348  0cn0 12553  cz 12639  cuz 12903  ...cfz 13567  cexp 14112  abscabs 15283  cprime 16718  ℤ[i]cgz 16976
This theorem was proved from axioms:  ax-mp 5  ax-1 6  ax-2 7  ax-3 8  ax-gen 1793  ax-4 1807  ax-5 1909  ax-6 1967  ax-7 2007  ax-8 2110  ax-9 2118  ax-10 2141  ax-11 2158  ax-12 2178  ax-ext 2711  ax-rep 5303  ax-sep 5317  ax-nul 5324  ax-pow 5383  ax-pr 5447  ax-un 7770  ax-cnex 11240  ax-resscn 11241  ax-1cn 11242  ax-icn 11243  ax-addcl 11244  ax-addrcl 11245  ax-mulcl 11246  ax-mulrcl 11247  ax-mulcom 11248  ax-addass 11249  ax-mulass 11250  ax-distr 11251  ax-i2m1 11252  ax-1ne0 11253  ax-1rid 11254  ax-rnegex 11255  ax-rrecex 11256  ax-cnre 11257  ax-pre-lttri 11258  ax-pre-lttrn 11259  ax-pre-ltadd 11260  ax-pre-mulgt0 11261  ax-pre-sup 11262
This theorem depends on definitions:  df-bi 207  df-an 396  df-or 847  df-3or 1088  df-3an 1089  df-tru 1540  df-fal 1550  df-ex 1778  df-nf 1782  df-sb 2065  df-mo 2543  df-eu 2572  df-clab 2718  df-cleq 2732  df-clel 2819  df-nfc 2895  df-ne 2947  df-nel 3053  df-ral 3068  df-rex 3077  df-rmo 3388  df-reu 3389  df-rab 3444  df-v 3490  df-sbc 3805  df-csb 3922  df-dif 3979  df-un 3981  df-in 3983  df-ss 3993  df-pss 3996  df-nul 4353  df-if 4549  df-pw 4624  df-sn 4649  df-pr 4651  df-op 4655  df-uni 4932  df-int 4971  df-iun 5017  df-br 5167  df-opab 5229  df-mpt 5250  df-tr 5284  df-id 5593  df-eprel 5599  df-po 5607  df-so 5608  df-fr 5652  df-we 5654  df-xp 5706  df-rel 5707  df-cnv 5708  df-co 5709  df-dm 5710  df-rn 5711  df-res 5712  df-ima 5713  df-pred 6332  df-ord 6398  df-on 6399  df-lim 6400  df-suc 6401  df-iota 6525  df-fun 6575  df-fn 6576  df-f 6577  df-f1 6578  df-fo 6579  df-f1o 6580  df-fv 6581  df-riota 7404  df-ov 7451  df-oprab 7452  df-mpo 7453  df-om 7904  df-1st 8030  df-2nd 8031  df-frecs 8322  df-wrecs 8353  df-recs 8427  df-rdg 8466  df-1o 8522  df-2o 8523  df-oadd 8526  df-er 8763  df-en 9004  df-dom 9005  df-sdom 9006  df-fin 9007  df-sup 9511  df-inf 9512  df-dju 9970  df-card 10008  df-pnf 11326  df-mnf 11327  df-xr 11328  df-ltxr 11329  df-le 11330  df-sub 11522  df-neg 11523  df-div 11948  df-nn 12294  df-2 12356  df-3 12357  df-4 12358  df-n0 12554  df-xnn0 12626  df-z 12640  df-uz 12904  df-rp 13058  df-fz 13568  df-fl 13843  df-mod 13921  df-seq 14053  df-exp 14113  df-hash 14380  df-cj 15148  df-re 15149  df-im 15150  df-sqrt 15284  df-abs 15285  df-dvds 16303  df-gcd 16541  df-prm 16719  df-gz 16977
This theorem is referenced by:  4sq  17011
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