Paper

• Classification of non-degenerate regular polyhedral complexes of positive curvature
  Fumiko Ohtsuka, Department of Mathematics, Faculty of Science
  Mathematical Journal of Ibaraki University, 2024, [Reviewed]
• 〔Major achievements〕Some geometric properties of regular polyhedral complexes
  Fumiko Ohtsuka
  Math. J. Ibaraki Univ., Aug. 2022, [Reviewed]
• Structure of 2-skeletons of higher dimensional regular polytopes　　　　　　　　　　　　　　　
  Fumiko Ohtsuka
  Math. J. Ibaraki Univ., 2018, [Reviewed]
• A natural generalization of regular convex polyhedra
  Jin-ichi Itoh; Fumiko Ohtsuka, Lead
  TOPOLOGY AND ITS APPLICATIONS, Mar. 2017, [Reviewed]
• Some remarks on simple closed geodesics of surfaces with ends
  Jin-ichi Itoh; Fumiko Ohtsuka and Tudor Zamfirescu, Lead
  Bull. Math. Soc. Sci. Math. Roumanie, 2009, [Reviewed]
• Total curvature of noncompact piecewise Riemannian 2-polyhedra
  Jin-ichi Itoh; Fumiko Ohtsuka, Lead, Institute of Mathematics, University of Tsukuba
  Tsukuba J. Math., 2005, [Reviewed]
• Erratum to: "Structure of flat piecewise Riemannian 2-polyhedra"
  Fumiko Ohtsuka, The object of our research is a piecewise Riemannian 2-polyhedron which is a combinatorial 2-polyhedron such that each 2-simplex is isometric to a triangle bounded by three smooth curves on some Riemannian 2-manifold. In the previous paper [4], which is a joint work with J. Itoh, we have introduced the concept of total curvature for piecewise Riemannian 2-polyhedra and proved a generalized Gauss-Bonnet theorem and a generalized Cohn-Vossen theorem. In this paper, we shall give a definition of flatness of piecewise Riemannian 2-polyhedra and characterize them., Faculty of Science, Ibaraki University
  Math. J. Ibaraki Univ., 2005
• Structure of flat piecewise Riemannian 2-polyhedra
  Fumiko Ohtsuka, The object of our research is a piecewise Riemannian 2-polyhedron which is a combinatorial 2-polyhedron such that each 2-simplex is isometric to a triangle bounded by three smooth curves on some Riemannian 2-manifold. In the previous paper [4], which is a joint work with J. Itoh, we have introduced the concept of total curvature for piecewise Riemannian 2-polyhedra and proved a generalized Gauss-Bonnet theorem and a generalized Cohn-Vossen theorem. In this paper, we shall give a definition of flatness of piecewise Riemannian 2-polyhedra and characterize them., Faculty of Science, Ibaraki University
  Math. J. Ibaraki Univ., 2004, [Reviewed]
• Total excess on length surfaces
  Yoshiroh Machigashira; Fumiko Ohtsuka, Corresponding
  Mathematische Annalen, 2001, [Reviewed]
• Total excess and Tits metric for piecewise Riemannian 2-manifolds
  Kazuhiro Kawamura; Fumiko Ohtsuka, Lead
  Topology and its Applications, 1999, [Reviewed]
• The existence of a straight line of piecewise Riemannian 2-manifolds　　　　　　　　　　　　　　　
  Kazuhiro Kawamura; Fumiko Ohtsuka, Lead
  Note di Matematica, 1998, [Reviewed]
• Hausdorff approximations on Hadamard manifolds and their ideal boundaries　　　　　　　　　　　　　　　
  Fumiko Ohtsuka
  Tsukuba Journal of Mathematics, 1996, [Reviewed]
• Rigidity of compact ideal boundaries of manifolds joined by Hausdorff approximations
  Fumiko Ohtsuka, The concept of ideal boundary of Hadamard monifolds was introduced by Eberlein and O'Neill [3] in 1973, which had marked a millestone is the study of the geometry of noncompact Reimannian manifolds. Since then, it has been utilized in various fields of research on Hadamard manifolds. ..., University of Tsukuba
  Tsukuba Journal of Mathematics, 1994, [Reviewed]
• The Euclidean factor of a Hadamard manifold
  Toshiaki Adachi; Fumiko Ohtsuka
  Proceedings of the American mathematical Society, 1991, [Reviewed]
• On manifolds having some restricted ideal boundaries
  Fumiko Ohtsuka
  Geometriae Dedicata, 1991, [Reviewed]
• On a relation between the total curvature and Tits metric
  Fumiko Ohtsuka, Faculty of Science, Ibaraki University
  Bulletin of the Faculity of Science, Ibaraki University, Series A, 1988, [Reviewed]
• On the existence of a straight line
  Fumiko Ohtsuka, University of Tsukuba
  Tsukuba Journal of Mathematics, 1988, [Reviewed]
• Complete 2-transnormal hypersurfaces in a kaehler manifold of negative constant holomorphic sectional curvature
  Fumiko Ohtsuka, University of Tsukuba
  Tsukuba Journal of Mathematics, 1987, [Reviewed]
• Compact 2-transnormal hypersurface in a kaehler manifold of constant holomorphic sectional curvature
  Fumiko Ohtsuka, University of Tsukuba
  Tsukuba Journal of Mathematics, 1986, [Reviewed]