Arithmetics and combinatorics of tropical Severi varieties of univariate polynomials

We give a description of the tropical Severi variety of univariate polynomials of degree n having two double roots. We show that, as a set, it is given as the union of three explicit types of cones of maximal dimension n − 1, where only cones of two of these types are cones of the secondary fan of {...

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Detalles Bibliográficos
Autores principales: Dickenstein, A., Herrero, M.I., Tabera, L.F.
Formato: JOUR
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00212172_v221_n2_p741_Dickenstein
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Sumario:We give a description of the tropical Severi variety of univariate polynomials of degree n having two double roots. We show that, as a set, it is given as the union of three explicit types of cones of maximal dimension n − 1, where only cones of two of these types are cones of the secondary fan of {0,.., n}. Through Kapranov’s theorem, this goal is achieved by a careful study of the possible valuations of the elementary symmetric functions of the roots of a polynomial with two double roots. Despite its apparent simplicity, the computation of the tropical Severi variety has both combinatorial and arithmetic ingredients. © 2017, Hebrew University of Jerusalem.