On Alexander-Conway polynomials of two-bridge links

Pierre-Vincent Koseleff (1, 2, 3) , Daniel Pecker (1, 2, 3)

1 UPMC - Université Pierre et Marie Curie - Paris 6
2 IMJ - Institut de Mathématiques de Jussieu
3 OURAGAN - OUtils de Résolution Algébriques pour la Géométrie et ses ApplicatioNs

We consider Conway polynomials of two-bridge links as Euler continuant polynomials. As a consequence, we obtain new and elementary proofs of classical Murasugi's 1958 alternating theorem and Hartley's 1979 trapezoidal theorem. We give a modulo 2 congruence for links, which implies the classical Murasugi's 1971 congruence for knots. We also give sharp bounds for the coefficients of Euler continuants and deduce bounds for the Alexander polynomials of two-bridge links. These bounds improve and generalize those of Nakanishi Suketa'96. We easily obtain some bounds for the roots of the Alexander polynomials of two-bridge links. This is a partial answer to Hoste's conjecture on the roots of Alexander polynomials of alternating knots.

Mots clés: Euler continuant polynomial; two-bridge link; Conway polynomial; Alexander polynomial

Domaines: Topologie géométrique [math.GT]

Pierre-Vincent Koseleff, Daniel Pecker. On Alexander-Conway polynomials of two-bridge links. 2013. ⟨hal-00778808v2⟩