Feuille d`exercices 1, correction

k m ≥1
mk = 0 Z/nZn mk Z
k n
n mk n m
m≥1m=n k
n
d k n
k=dk0n=dn0k0n0n
mk d d 6= 0 Z
n0mk0
n0
m m =n0n0k=n0dk0=nk0
n k n0
n/pgcd(k, n)