let p, i, n be Nat; :: thesis: ( p > 1 & (i |^ n) mod p = 1 & i,p are_relative_prime implies order i,p divides n )
assume that
A1: p > 1 and
A2: (i |^ n) mod p = 1 and
A3: i,p are_relative_prime ; :: thesis: order i,p divides n
A4: order i,p <> 0 by A1, A3, Def2;
A5: (i |^ (order i,p)) mod p = 1 by A1, A3, Def2;
n mod (order i,p) = 0
proof
set I = n mod (order i,p);
consider t being Nat such that
A6: n = ((order i,p) * t) + (n mod (order i,p)) and
A7: n mod (order i,p) < order i,p by A4, NAT_D:def 2;
reconsider t = t as Element of NAT by ORDINAL1:def 13;
((i |^ ((order i,p) * t)) * (i |^ (n mod (order i,p)))) mod p = 1 by A2, A6, NEWTON:13;
then (((i |^ (order i,p)) |^ t) * (i |^ (n mod (order i,p)))) mod p = 1 by NEWTON:14;
then ((((i |^ (order i,p)) |^ t) mod p) * (i |^ (n mod (order i,p)))) mod p = 1 by EULER_2:10;
then A8: (1 * (i |^ (n mod (order i,p)))) mod p = 1 by A1, A5, Th36;
assume n mod (order i,p) <> 0 ; :: thesis: contradiction
hence contradiction by A1, A3, A7, A8, Def2; :: thesis: verum
end;
hence order i,p divides n by A4, Th6; :: thesis: verum