19 citations · 63 across the 20 of their papers we have counts for
20 papers
Realizing crosscap transpositions as monodromies of singular fibrations
Kenta Hayano
We introduce a new type of singularity for smooth maps from -manifolds to surfaces, called an -singularity, whose critical locus is a circle contained in a single fiber. We s…
Constraint Qualification for Generic Parameter Families of Constraints in Optimization
Naoki Hamada, Kenta Hayano, Hiroshi Teramoto
Constraint qualifications (CQs) are central to the local analysis of constrained optimization. In this paper, we completely determine the validity of the four classical CQs -- LICQ…
Combinatorial construction of symplectic 6-manifolds via bifibration structures
Kenta Hayano
A bifibration structure on a -manifold is a map to either the complex projective plane or a -bundle over , such that its composition w…
Characterization of generic parameter families of constraint mappings in optimization
Naoki Hamada, Kenta Hayano, Hiroshi Teramoto
The purpose of this paper is to understand generic behavior of constraint functions in optimization problems relying on singularity theory of smooth mappings. To this end, we will…
Classification of genus- holomorphic Lefschetz pencils
Noriyuki Hamada, Kenta Hayano
In this paper, we classify relatively minimal genus- holomorphic Lefschetz pencils up to smooth isomorphism. We first show that such a pencil is isomorphic to either the pencil…
Topology of Pareto sets of strongly convex problems
Naoki Hamada, Kenta Hayano, Shunsuke Ichiki +2
A multiobjective optimization problem is simplicial if the Pareto set and front are homeomorphic to a simplex and, under the homeomorphisms, each face of the simplex corresponds to…
Unchaining surgery and topology of symplectic 4-manifolds
R. Inanc Baykur, Kenta Hayano, Naoyuki Monden
We study a symplectic surgery operation we call unchaining, which effectively reduces the second Betti number and the symplectic Kodaira dimension at the same time. Using unchainin…
Stability of non-proper functions
Kenta Hayano
The purpose of this paper is to give a sufficient condition for (strong) stability of non-proper smooth functions (with respect to the Whitney -topology). We show that a…
On diagrams of simplified trisections and mapping class groups
Kenta Hayano
A simplified trisection is a trisection map on a 4-manifold such that, in its critical value set, there is no double point and cusps only appear in triples on innermost fold circle…
Topology of holomorphic Lefschetz pencils on the four-torus
Noriyuki Hamada, Kenta Hayano
In this paper we discuss topological properties of holomorphic Lefschetz pencils on the four-torus. Relying on the theory of moduli spaces of polarized abelian surfaces, we first p…
Hurwitz equivalence for Lefschetz fibrations and their multisections
R. Inanc Baykur, Kenta Hayano
In this article, we characterize isomorphism classes of Lefschetz fibrations with multisections via their monodromy factorizations. We prove that two Lefschetz fibrations with mult…
Broken Lefschetz fibrations and mapping class groups
R. Inanc Baykur, Kenta Hayano
The purpose of this note is to explain a combinatorial description of closed smooth oriented 4-manifolds in terms of positive Dehn twist factorizations of surface mapping classes,…
Multisections of Lefschetz fibrations and topology of symplectic 4-manifolds
R. Inanc Baykur, Kenta Hayano
We initiate a study of positive multisections of Lefschetz fibrations via positive factorizations in framed mapping class groups of surfaces. Using our methods, one can effectively…
C^\infty-logarithmic transformations and generalized complex structures
Ryushi Goto, Kenta Hayano
Applying logarithmic transformations along 2-tori, we construct a generalized complex structure J_n with n type changing luci for every on genus 1-Lefschetz fibrations wi…
Elimination of cusps in dimension 4 and its applications
Stefan Behrens, Kenta Hayano
Several new combinatorial descriptions of closed 4-manifolds have recently been introduced in the study of smooth maps from 4-manifolds to surfaces. These descriptions consist of s…
Modification rule of monodromies in R_2-move
Kenta Hayano
An R_2-move is a homotopy of wrinkled fibrations which deforms images of indefinite fold singularities like Reidemeister move of type II. Variants of this move are contained in sev…
A signature formula for hyperelliptic broken Lefschetz fibrations
Kenta Hayano, Masatoshi Sato
A hyperelliptic broken Lefschetz fibration is a generalization of a hyperelliptic Lefschetz fibration. We construct and compute a local signature of hyperelliptic directed broken L…
Four-manifolds admitting hyperelliptic broken Lefschetz fibrations
Kenta Hayano, Masatoshi Sato
We introduce hyperelliptic simplified (more generally, directed) broken Lefschetz fibrations, which is a generalization of hyperelliptic Lefschetz fibrations. We construct involuti…
A note on sections of broken Lefschetz fibrations
Kenta Hayano
We show that there exists a non-trivial simplified broken Lefschetz fibration which has infinitely many homotopy classes of sections. We also construct a non-trivial simplified bro…
On genus-1 simplified broken Lefschetz fibrations
Kenta Hayano
Auroux, Donaldson and Katzarkov introduced broken Lefschetz fibrations as a generalization of Lefshcetz fibrations in order to describe near-symplectic 4-manifolds. We first study…