Metamath Proof Explorer

Theorem lgsval

Description: Value of the Legendre symbol at an arbitrary integer. (Contributed by Mario Carneiro, 4-Feb-2015)

Ref Expression
Hypothesis lgsval.1 
|- F = ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || A , 0 , if ( ( A mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt N ) ) , 1 ) )
Assertion lgsval 
|- ( ( A e. ZZ /\ N e. ZZ ) -> ( A /L N ) = if ( N = 0 , if ( ( A ^ 2 ) = 1 , 1 , 0 ) , ( if ( ( N < 0 /\ A < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , F ) ` ( abs ` N ) ) ) ) )

Proof

Step Hyp Ref Expression
1 lgsval.1 
 |-  F = ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || A , 0 , if ( ( A mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt N ) ) , 1 ) )
2 simpr 
 |-  ( ( a = A /\ m = N ) -> m = N )
3 2 eqeq1d 
 |-  ( ( a = A /\ m = N ) -> ( m = 0 <-> N = 0 ) )
4 simpl 
 |-  ( ( a = A /\ m = N ) -> a = A )
5 4 oveq1d 
 |-  ( ( a = A /\ m = N ) -> ( a ^ 2 ) = ( A ^ 2 ) )
6 5 eqeq1d 
 |-  ( ( a = A /\ m = N ) -> ( ( a ^ 2 ) = 1 <-> ( A ^ 2 ) = 1 ) )
7 6 ifbid 
 |-  ( ( a = A /\ m = N ) -> if ( ( a ^ 2 ) = 1 , 1 , 0 ) = if ( ( A ^ 2 ) = 1 , 1 , 0 ) )
8 2 breq1d 
 |-  ( ( a = A /\ m = N ) -> ( m < 0 <-> N < 0 ) )
9 4 breq1d 
 |-  ( ( a = A /\ m = N ) -> ( a < 0 <-> A < 0 ) )
10 8 9 anbi12d 
 |-  ( ( a = A /\ m = N ) -> ( ( m < 0 /\ a < 0 ) <-> ( N < 0 /\ A < 0 ) ) )
11 10 ifbid 
 |-  ( ( a = A /\ m = N ) -> if ( ( m < 0 /\ a < 0 ) , -u 1 , 1 ) = if ( ( N < 0 /\ A < 0 ) , -u 1 , 1 ) )
12 4 breq2d 
 |-  ( ( a = A /\ m = N ) -> ( 2 || a <-> 2 || A ) )
13 4 oveq1d 
 |-  ( ( a = A /\ m = N ) -> ( a mod 8 ) = ( A mod 8 ) )
14 13 eleq1d 
 |-  ( ( a = A /\ m = N ) -> ( ( a mod 8 ) e. { 1 , 7 } <-> ( A mod 8 ) e. { 1 , 7 } ) )
15 14 ifbid 
 |-  ( ( a = A /\ m = N ) -> if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) = if ( ( A mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) )
16 12 15 ifbieq2d 
 |-  ( ( a = A /\ m = N ) -> if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) = if ( 2 || A , 0 , if ( ( A mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) )
17 4 oveq1d 
 |-  ( ( a = A /\ m = N ) -> ( a ^ ( ( n - 1 ) / 2 ) ) = ( A ^ ( ( n - 1 ) / 2 ) ) )
18 17 oveq1d 
 |-  ( ( a = A /\ m = N ) -> ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) = ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) )
19 18 oveq1d 
 |-  ( ( a = A /\ m = N ) -> ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) = ( ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) )
20 19 oveq1d 
 |-  ( ( a = A /\ m = N ) -> ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) = ( ( ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) )
21 16 20 ifeq12d 
 |-  ( ( a = A /\ m = N ) -> if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) = if ( n = 2 , if ( 2 || A , 0 , if ( ( A mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) )
22 2 oveq2d 
 |-  ( ( a = A /\ m = N ) -> ( n pCnt m ) = ( n pCnt N ) )
23 21 22 oveq12d 
 |-  ( ( a = A /\ m = N ) -> ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) = ( if ( n = 2 , if ( 2 || A , 0 , if ( ( A mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt N ) ) )
24 23 ifeq1d 
 |-  ( ( a = A /\ m = N ) -> if ( n e. Prime , ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) , 1 ) = if ( n e. Prime , ( if ( n = 2 , if ( 2 || A , 0 , if ( ( A mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt N ) ) , 1 ) )
25 24 mpteq2dv 
 |-  ( ( a = A /\ m = N ) -> ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) , 1 ) ) = ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || A , 0 , if ( ( A mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( A ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt N ) ) , 1 ) ) )
26 25 1 eqtr4di 
 |-  ( ( a = A /\ m = N ) -> ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) , 1 ) ) = F )
27 26 seqeq3d 
 |-  ( ( a = A /\ m = N ) -> seq 1 ( x. , ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) , 1 ) ) ) = seq 1 ( x. , F ) )
28 2 fveq2d 
 |-  ( ( a = A /\ m = N ) -> ( abs ` m ) = ( abs ` N ) )
29 27 28 fveq12d 
 |-  ( ( a = A /\ m = N ) -> ( seq 1 ( x. , ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) , 1 ) ) ) ` ( abs ` m ) ) = ( seq 1 ( x. , F ) ` ( abs ` N ) ) )
30 11 29 oveq12d 
 |-  ( ( a = A /\ m = N ) -> ( if ( ( m < 0 /\ a < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) , 1 ) ) ) ` ( abs ` m ) ) ) = ( if ( ( N < 0 /\ A < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , F ) ` ( abs ` N ) ) ) )
31 3 7 30 ifbieq12d 
 |-  ( ( a = A /\ m = N ) -> if ( m = 0 , if ( ( a ^ 2 ) = 1 , 1 , 0 ) , ( if ( ( m < 0 /\ a < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) , 1 ) ) ) ` ( abs ` m ) ) ) ) = if ( N = 0 , if ( ( A ^ 2 ) = 1 , 1 , 0 ) , ( if ( ( N < 0 /\ A < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , F ) ` ( abs ` N ) ) ) ) )
32 df-lgs 
 |-  /L = ( a e. ZZ , m e. ZZ |-> if ( m = 0 , if ( ( a ^ 2 ) = 1 , 1 , 0 ) , ( if ( ( m < 0 /\ a < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , ( n e. NN |-> if ( n e. Prime , ( if ( n = 2 , if ( 2 || a , 0 , if ( ( a mod 8 ) e. { 1 , 7 } , 1 , -u 1 ) ) , ( ( ( ( a ^ ( ( n - 1 ) / 2 ) ) + 1 ) mod n ) - 1 ) ) ^ ( n pCnt m ) ) , 1 ) ) ) ` ( abs ` m ) ) ) ) )
33 1nn0 
 |-  1 e. NN0
34 0nn0 
 |-  0 e. NN0
35 33 34 ifcli 
 |-  if ( ( A ^ 2 ) = 1 , 1 , 0 ) e. NN0
36 35 elexi 
 |-  if ( ( A ^ 2 ) = 1 , 1 , 0 ) e. _V
37 ovex 
 |-  ( if ( ( N < 0 /\ A < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , F ) ` ( abs ` N ) ) ) e. _V
38 36 37 ifex 
 |-  if ( N = 0 , if ( ( A ^ 2 ) = 1 , 1 , 0 ) , ( if ( ( N < 0 /\ A < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , F ) ` ( abs ` N ) ) ) ) e. _V
39 31 32 38 ovmpoa 
 |-  ( ( A e. ZZ /\ N e. ZZ ) -> ( A /L N ) = if ( N = 0 , if ( ( A ^ 2 ) = 1 , 1 , 0 ) , ( if ( ( N < 0 /\ A < 0 ) , -u 1 , 1 ) x. ( seq 1 ( x. , F ) ` ( abs ` N ) ) ) ) )