English
Related papers

Related papers: Explicit round fold maps on some fundamental manif…

200 papers

The canonical projections of the unit spheres are generalized to special generic maps and round fold maps, for example. They are generalizations from the viewpoint of singularity theory of differentiable maps and these maps restrict the…

Algebraic Geometry · Mathematics 2026-02-13 Naoki Kitazawa

A so-called special generic map is by definition a map of smooth manifolds all of whose singularities are definite fold points. It is in general an open problem posed by Saeki in 1993 to determine the set of integers $p$ for which a given…

Geometric Topology · Mathematics 2018-03-28 Dominik Wrazidlo

As a branch of algebraic and differential topology of manifolds, the theory of Morse functions and their higher dimensional versions or fold maps and its application to algebraic and differential topology of manifolds is fundamental,…

K-Theory and Homology · Mathematics 2020-05-26 Naoki Kitazawa

Special generic maps are smooth maps between smooth manifolds with only definite fold points as their singularities. The problem of whether a closed $n$-manifold admits a special generic map into Euclidean $p$-space for $1 \leq p \leq n$…

Geometric Topology · Mathematics 2020-09-15 Dominik Wrazidlo

Graph manifolds form important classes of $3$-dimensional closed and orientable manifolds. For example, {\it Seifert} manifolds are graph manifolds where hyperbolic manifolds are not. In applying singularity theory of differentiable maps to…

Geometric Topology · Mathematics 2022-08-16 Naoki Kitazawa

We study how to construct explicit deformations of generic smooth maps from closed $n$--dimensional manifolds $M$ with $n \geq 2$ to the $2$--sphere $S^2$ and show that every smooth map $M \to S^2$ is homotopic to a $C^\infty$ stable map…

Geometric Topology · Mathematics 2025-05-30 Osamu Saeki

Special generic maps are generalizations of Morse functions with exactly two singular points on spheres and canonical projections of unit spheres. They restrict the manifolds of the domains strongly in considerable cases and are important…

Algebraic Topology · Mathematics 2023-03-01 Naoki Kitazawa

Special-generic-like maps or SGL maps are introduced by the author motivated by observing and investigating algebraic topological or differential topological properties of manifolds via nice smooth maps whose codimensions are negative. The…

Algebraic Topology · Mathematics 2023-03-20 Naoki Kitazawa

In studies of smooth maps with good differential topological conditions such as immersions, embeddings, Morse functions and their higher dimensional versions including fold maps and application to geometry, especially algebraic and…

Geometric Topology · Mathematics 2019-01-23 Naoki Kitazawa

As Reeb's theorem shows, Morse functions with exactly two singular points on closed manifolds are very simple and important. They characterize spheres whose dimensions are not $4$ topologically and the $4$-dimensional unit sphere. Special…

Algebraic Topology · Mathematics 2022-10-24 Naoki Kitazawa

Submersions with definite folds are submersions on manifolds with boundary whose restrictions to the boundary are definite fold maps. In this paper, we study the properties from the viewpoint of differential topology of manifolds with…

Geometric Topology · Mathematics 2026-04-30 Koki Iwakura

We show that a closed orientable 3--dimensional manifold admits a round fold map into the plane, i.e. a fold map whose critical value set consists of disjoint simple closed curves isotopic to concentric circles, if and only if it is a graph…

Geometric Topology · Mathematics 2023-11-15 Naoki Kitazawa , Osamu Saeki

In this paper, as a fundamental study on the theory of Morse functions and their higher dimensional versions or fold maps and applications to geometric theory of manifolds, which were started in 1950s by differential topologists such as…

K-Theory and Homology · Mathematics 2019-01-08 Naoki Kitazawa

Closed (and simply-connected) manifolds whose dimensions are greater than 4 are classified via sophisticated algebraic and abstract theory such as surgery theory and homotopy theory. It is difficult to handle 3 or 4-dimensional closed…

Algebraic Topology · Mathematics 2021-09-24 Naoki Kitazawa

As a higher dimensional version of the theory of Morse functions, there have been various studies of smooth manifolds using generic smooth maps. As fundamental results, in these studies, they have found that inverse images of such maps…

Algebraic Topology · Mathematics 2018-12-21 Naoki Kitazawa

Fold maps are higher dimensional versions of Morse functions and fundamental and important tools in studying algebraic and differential topological properties of manifolds: as the theory established by Morse and the higher dimensional…

Geometric Topology · Mathematics 2019-06-20 Naoki Kitazawa

A Reeb space is defined as the space of all the connected components of inverse images of a smooth map, which is a fundamental tool in studying smooth manifolds using generic smooth maps whose codimensions are not positive such as Morse…

Geometric Topology · Mathematics 2018-05-29 Naoki Kitazawa

We have been interested in understanding the class of 7-dimensional closed and simply-connected manifolds in geometric and constructive ways. We have constructed explicit fold maps, which are higher dimensional versions of Morse functions,…

Algebraic Topology · Mathematics 2022-04-11 Naoki Kitazawa

Constructing Morse functions and their higher dimensional versions or fold maps is fundamental, important and challenging in investigating the topologies and the differentiable structures of differentiable manifolds via Morse functions,…

Geometric Topology · Mathematics 2020-11-12 Naoki Kitazawa

The theory of Morse functions and their higher dimensional versions or fold maps on manifolds and its application to geometric theory of manifolds is one of important branches of geometry and mathematics. Studies related to this was started…

Geometric Topology · Mathematics 2020-07-21 Naoki Kitazawa