Naoyuki Koike Laboratory

DIFFERENTIAL GEOMETRY / TOPOLOGY / GEOMETRIC ANALYSIS

My research focuses on submanifold geometry in symmetric spaces, and on mean curvature flow and inverse mean curvature flow — geometric flows closely related to the Ricci flow used in the resolution of the Poincaré conjecture. I am also interested in connections with general relativity and gauge theory.

Photo of Naoyuki Koike (July 21, 2025)

Research Themes

Overview
1

Submanifolds in symmetric spaces of compact type

Reduction to the study of submanifolds in an infinite-dimensional Hilbert space via a Riemannian submersion, exploiting the flatness and absolute parallelism of the Hilbert space.

2

Submanifolds in symmetric spaces of non-compact type

Reduction via complexification (anti-Kaehler submanifolds) to the study of submanifolds in an infinite-dimensional anti-Kaehler space.

3

Mean curvature flow and inverse mean curvature flow in symmetric spaces

Collapse, divergence and convergence behaviour of submanifolds evolving under (modified) mean curvature flow equations.

4

Topology of hypersurfaces via mean curvature flow with surgery

Defining mean curvature flow with surgery for certain hypersurfaces and applying it to study their topology.

Books

In Japanese
  1. Signpost of Topological Space — From Foundation to Topological Invariants, Kyoritsu Shuppan, 2025, 280 pp.
  2. Vector Analysis & Differential Geometry Enlightened by Integral Formulas — From Stokes' Theorem to Variational Formula, Kyoritsu Shuppan, 2022, 385 pp.
  3. Submanifold Geometry Hidden in Theoretical Physics — Connection with General Theory of Relativity and Gauge Theory, Kyoritsu Shuppan, 2021, 438 pp.
  4. Mean Curvature Flow — Time Evolution of Submanifolds, Kyoritsu Shuppan, 2019, 376 pp.
Full list of publications

Simulations

Mean Curvature Flow

Interactive mean curvature flow simulators

Browser-based simulators developed with AI by a graduate student in my laboratory (released May 29, 2026).