show/hide this revision's text 2 added 7 characters in body

Those polynomials are irreducible in $\Z[X]$ \mathbb Z[X]$ and have different degree... see http://en.wikipedia.org/wiki/Cyclotomic_polynomial

show/hide this revision's text 1

Those polynomials are irreducible in $\Z[X]$ and have different degree... see http://en.wikipedia.org/wiki/Cyclotomic_polynomial