Factorization of polynomials over finite fields: Difference between revisions

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Irreducible polynomials: Correction of enumeration formula
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Irreducible polynomials over finite fields are also useful for [[Pseudorandom]] number generators using feedback shift registers and [[discrete logarithm]] over '''F'''<sub>2<sup>''n''</sup></sub>.
 
The number of primary (i.e. power of an irreducible) [[monic polynomial]]s of degree ''n'' over '''F'''<sub>''pq''</sub> (for ''p'' prime) is equal to the [[Necklace (combinatorics)|necklace counting function]] ''N''<sub>''pq''</sub>(''n'').<ref>Christophe Reutenauer, ''Mots circulaires et polynomes irreductibles'', Ann. Sci. math Quebec, vol 12, no 2, pp. 275-285</ref> Alternatively, one may consider this as the number of irreducible polynomials of all degrees d dividing n;
to get the number of irreducibles of degree exactly n, one must useapplies [[Mobius inversion formula|Mobius inversion]].
 
====Example====