Definition df-lgs 15997

Description: Define the Legendre symbol (actually the Kronecker symbol, which extends the Legendre symbol to all integers, and also the Jacobi symbol, which restricts the Kronecker symbol to positive odd integers). See definition in [ApostolNT] p. 179 resp. definition in [ApostolNT] p. 188. (Contributed by Mario Carneiro, 4-Feb-2015.)

Assertion

Ref	Expression
df-lgs	⊢ /L = (𝑎 ∈ ℤ, 𝑛 ∈ ℤ ↦ if(𝑛 = 0, if((𝑎↑2) = 1, 1, 0), (if((𝑛 < 0 ∧ 𝑎 < 0), -1, 1) · (seq1( · , (𝑚 ∈ ℕ ↦ if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1)))‘(abs‘𝑛)))))

Distinct variable group:   𝑚,𝑎,𝑛

Detailed syntax breakdown of Definition df-lgs

Step	Hyp	Ref	Expression
1		clgs 15996	. 2 class /L
2		va	. . 3 setvar 𝑎
3		vn	. . 3 setvar 𝑛
4		cz 9594	. . 3 class ℤ
5	3	cv 1397	. . . . 5 class 𝑛
6		cc0 8143	. . . . 5 class 0
7	5, 6	wceq 1398	. . . 4 wff 𝑛 = 0
8	2	cv 1397	. . . . . . 7 class 𝑎
9		c2 9305	. . . . . . 7 class 2
10		cexp 10924	. . . . . . 7 class ↑
11	8, 9, 10	co 6058	. . . . . 6 class (𝑎↑2)
12		c1 8144	. . . . . 6 class 1
13	11, 12	wceq 1398	. . . . 5 wff (𝑎↑2) = 1
14	13, 12, 6	cif 3624	. . . 4 class if((𝑎↑2) = 1, 1, 0)
15		clt 8324	. . . . . . . 8 class <
16	5, 6, 15	wbr 4114	. . . . . . 7 wff 𝑛 < 0
17	8, 6, 15	wbr 4114	. . . . . . 7 wff 𝑎 < 0
18	16, 17	wa 104	. . . . . 6 wff (𝑛 < 0 ∧ 𝑎 < 0)
19	12	cneg 8461	. . . . . 6 class -1
20	18, 19, 12	cif 3624	. . . . 5 class if((𝑛 < 0 ∧ 𝑎 < 0), -1, 1)
21		cabs 11707	. . . . . . 7 class abs
22	5, 21	cfv 5357	. . . . . 6 class (abs‘𝑛)
23		cmul 8148	. . . . . . 7 class ·
24		vm	. . . . . . . 8 setvar 𝑚
25		cn 9254	. . . . . . . 8 class ℕ
26	24	cv 1397	. . . . . . . . . 10 class 𝑚
27		cprime 12829	. . . . . . . . . 10 class ℙ
28	26, 27	wcel 2205	. . . . . . . . 9 wff 𝑚 ∈ ℙ
29	26, 9	wceq 1398	. . . . . . . . . . 11 wff 𝑚 = 2
30		cdvds 12498	. . . . . . . . . . . . 13 class ∥
31	9, 8, 30	wbr 4114	. . . . . . . . . . . 12 wff 2 ∥ 𝑎
32		c8 9311	. . . . . . . . . . . . . . 15 class 8
33		cmo 10708	. . . . . . . . . . . . . . 15 class mod
34	8, 32, 33	co 6058	. . . . . . . . . . . . . 14 class (𝑎 mod 8)
35		c7 9310	. . . . . . . . . . . . . . 15 class 7
36	12, 35	cpr 3695	. . . . . . . . . . . . . 14 class {1, 7}
37	34, 36	wcel 2205	. . . . . . . . . . . . 13 wff (𝑎 mod 8) ∈ {1, 7}
38	37, 12, 19	cif 3624	. . . . . . . . . . . 12 class if((𝑎 mod 8) ∈ {1, 7}, 1, -1)
39	31, 6, 38	cif 3624	. . . . . . . . . . 11 class if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1))
40		cmin 8460	. . . . . . . . . . . . . . . . 17 class −
41	26, 12, 40	co 6058	. . . . . . . . . . . . . . . 16 class (𝑚 − 1)
42		cdiv 8963	. . . . . . . . . . . . . . . 16 class /
43	41, 9, 42	co 6058	. . . . . . . . . . . . . . 15 class ((𝑚 − 1) / 2)
44	8, 43, 10	co 6058	. . . . . . . . . . . . . 14 class (𝑎↑((𝑚 − 1) / 2))
45		caddc 8146	. . . . . . . . . . . . . 14 class +
46	44, 12, 45	co 6058	. . . . . . . . . . . . 13 class ((𝑎↑((𝑚 − 1) / 2)) + 1)
47	46, 26, 33	co 6058	. . . . . . . . . . . 12 class (((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚)
48	47, 12, 40	co 6058	. . . . . . . . . . 11 class ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1)
49	29, 39, 48	cif 3624	. . . . . . . . . 10 class if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))
50		cpc 13007	. . . . . . . . . . 11 class pCnt
51	26, 5, 50	co 6058	. . . . . . . . . 10 class (𝑚 pCnt 𝑛)
52	49, 51, 10	co 6058	. . . . . . . . 9 class (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛))
53	28, 52, 12	cif 3624	. . . . . . . 8 class if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1)
54	24, 25, 53	cmpt 4176	. . . . . . 7 class (𝑚 ∈ ℕ ↦ if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1))
55	23, 54, 12	cseq 10833	. . . . . 6 class seq1( · , (𝑚 ∈ ℕ ↦ if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1)))
56	22, 55	cfv 5357	. . . . 5 class (seq1( · , (𝑚 ∈ ℕ ↦ if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1)))‘(abs‘𝑛))
57	20, 56, 23	co 6058	. . . 4 class (if((𝑛 < 0 ∧ 𝑎 < 0), -1, 1) · (seq1( · , (𝑚 ∈ ℕ ↦ if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1)))‘(abs‘𝑛)))
58	7, 14, 57	cif 3624	. . 3 class if(𝑛 = 0, if((𝑎↑2) = 1, 1, 0), (if((𝑛 < 0 ∧ 𝑎 < 0), -1, 1) · (seq1( · , (𝑚 ∈ ℕ ↦ if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1)))‘(abs‘𝑛))))
59	2, 3, 4, 4, 58	cmpo 6060	. 2 class (𝑎 ∈ ℤ, 𝑛 ∈ ℤ ↦ if(𝑛 = 0, if((𝑎↑2) = 1, 1, 0), (if((𝑛 < 0 ∧ 𝑎 < 0), -1, 1) · (seq1( · , (𝑚 ∈ ℕ ↦ if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1)))‘(abs‘𝑛)))))
60	1, 59	wceq 1398	1 wff /L = (𝑎 ∈ ℤ, 𝑛 ∈ ℤ ↦ if(𝑛 = 0, if((𝑎↑2) = 1, 1, 0), (if((𝑛 < 0 ∧ 𝑎 < 0), -1, 1) · (seq1( · , (𝑚 ∈ ℕ ↦ if(𝑚 ∈ ℙ, (if(𝑚 = 2, if(2 ∥ 𝑎, 0, if((𝑎 mod 8) ∈ {1, 7}, 1, -1)), ((((𝑎↑((𝑚 − 1) / 2)) + 1) mod 𝑚) − 1))↑(𝑚 pCnt 𝑛)), 1)))‘(abs‘𝑛)))))

This definition is referenced by:  lgsval  16003