English

Irreducible polynomials with prescribed sums of coefficients

Number Theory 2016-05-03 v1

Abstract

Let qq be a power of a prime, let Fq\mathbb{F}_q be the finite field with qq elements and let n2n \geq 2. For a polynomial h(x)Fq[x]h(x) \in \mathbb{F}_q[x] of degree nNn \in \mathbb{N} and a subset W[0,n]:={0,1,,n}W \subseteq [0,n] := \{0, 1, \ldots, n\}, we define the sum-of-digits function SW(h)=wW[xw]h(x)S_W(h) = \sum_{w \in W}[x^{w}] h(x) to be the sum of all the coefficients of xwx^w in h(x)h(x) with wWw \in W. In the case when q=2q = 2, we prove, except for a few genuine exceptions, that for any cF2c \in \mathbb{F}_2 and any W[0,n]W \subseteq [0,n] there exists an irreducible polynomial P(x)P(x) of degree nn over F2\mathbb{F}_2 such that SW(P)=cS_{W}(P) = c. In particular, restricting ourselves to the case when #W=1\# W = 1, we obtain a new proof of the Hansen-Mullen irreducibility conjecture (now a theorem) in the case when q=2q = 2. In the case of q>2q> 2, we prove that, for any cFqc \in \mathbb{F}_q, any n2n\geq 2 and any W[0,n]W \subseteq [0,n], there exists an irreducible polynomial P(x)P(x) of degree nn such that SW(P)cS_{W}(P) \neq c.

Keywords

Cite

@article{arxiv.1605.00351,
  title  = {Irreducible polynomials with prescribed sums of coefficients},
  author = {Aleksandr Tuxanidy and Qiang Wang},
  journal= {arXiv preprint arXiv:1605.00351},
  year   = {2016}
}

Comments

arXiv admin note: text overlap with arXiv:1604.04023