suivant: Legendre symbol : legendre_symbol
monter: Integers (and Gaussian Integers)
précédent: Solving a2 + b2
Table des matières
Index
The Euler indicatrix : euler phi
euler (or phi) returns the Euler indicatrix
for a integer.
euler(n) (or phi(n)) is equal to the number of integers less
than n and prime with n.
Input :
euler(21)
Output :
12
In other words
E={2,4,5,7,8,10,11,13,15,16,17,19} is the set of integers less than 21
and coprime with 21. There are 12 members in this set, hence Cardinal(E)=12.
Euler has introduced this function to generalize the little Fermat theorem:
If a and n are mutually prime then
aeuler(n) = 1 mod n
giac documentation written by Renée De Graeve and Bernard Parisse