Definition 3. For a positive integer n, define μ by the rules
( )
( )
- =
=
=
if n p p p where p are distinct primes
if p n for some prime p
if n
n
r i
r 1 ... ,
0
1 1
1 2
m 2
Illustrations:
1. (30) (2 3 5) ( 1) 1 3 m = m × × = - = -
2. m (1) = 1, m (2) = -1, m (3) = -1, m (4) = 0 , m (5) = -1