Saddle point braids of braided fibrations and pseudo-fibrations

Let gt be a loop in the space of monic complex polynomials in one variable of fixed degree n. If the roots of gt are distinct for all t, they form a braid B1 on n strands. Likewise, if the critical points of gt are distinct for all t, they form a braid B2 on n-1 strands. In this paper we study the r...

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Detalles Bibliográficos
Autores: Bode, B., Hirasawa, M.
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2024
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/381553
Acceso en línea:http://hdl.handle.net/10261/381553
https://www.scopus.com/inward/record.uri?eid=2-s2.0-85190696117&doi=10.1007%2fs40687-024-00446-x&partnerID=40&md5=9c80691e3947731c99f4c5eadafef7f1
Access Level:acceso abierto
Palabra clave:14J17
14P25
30C10
32S55
57K10
Braided open book
Homogeneous braid
Isolated singularity
P-fibered braid
Real algebraic link
Saddle point braid
Descripción
Sumario:Let gt be a loop in the space of monic complex polynomials in one variable of fixed degree n. If the roots of gt are distinct for all t, they form a braid B1 on n strands. Likewise, if the critical points of gt are distinct for all t, they form a braid B2 on n-1 strands. In this paper we study the relationship between B1 and B2. Composing the polynomials gt with the argument map defines a pseudo-fibration map on the complement of the closure of B1 in C×S1, whose critical points lie on B2. We prove that for B1 a T-homogeneous braid and B2 the trivial braid this map can be taken to be a fibration map. In the case of homogeneous braids we present a visualization of this fact. Our work implies that for every pair of links L1 and L2 there is a mixed polynomial f:C2→C in complex variables u, v and the complex conjugate v¯ such that both f and the derivative fu have a weakly isolated singularity at the origin with L1 as the link of the singularity of f and L2 as a sublink of the link of the singularity of fu. © The Author(s) 2024.