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Ternary cyclotomic polynomials having a large coefficient

  • Yves Gallot and Pieter Moree
Published/Copyright: June 16, 2009
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Journal für die reine und angewandte Mathematik
From the journal Volume 2009 Issue 632

Abstract

Let Φn(x) denote the nth cyclotomic polynomial. In 1968 Sister Marion Beiter conjectured that an(k), the coefficient of xk in Φn(x), satisfies |an(k)| ≦ (p + 1)/2 in case n = pqr with p < q < r primes (in this case Φn(x) is said to be ternary). Since then several results towards establishing her conjecture have been proved (for example |an(k)| ≦ 3p/4). Here we show that, nevertheless, Beiter's conjecture is false for every p ≧ 11. We also prove that given any ε > 0 there exist infinitely many triples (pj, qj, rj) with p1 < p2 < ⋯ consecutive primes such that |apjqjrj(nj)| > (2/3 – ε)pj for j ≧ 1.

Received: 2007-12-12
Revised: 2008-03-19
Published Online: 2009-06-16
Published in Print: 2009-July

© Walter de Gruyter Berlin · New York 2009

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