On a problem of S. Ulam concerning Cartesian squares of 2-dimensional polyhedra
On aspherical presentations of groups.
On Cartesian powers of 2-polyhedra
On decomposition of 3-polyhedra into a Cartesian product
On equivariant deformations of maps.
We work in the smooth category: manifolds and maps are meant to be smooth. Let G be a finite group acting on a connected closed manifold X and f an equivariant self-map on X with f|A fixpointfree, where A is a closed invariant submanifold of X with codim A ≥ 3. The purpose of this paper is to give a proof using obstruction theory of the following fact: If X is simply connected and the action of G on X - A is free, then f is equivariantly deformable rel. A to fixed point free map if and only if the...
On framed links of Peiffer identities
On general dissections of a polygon.
On general dissections of a polygon. (Short Communication).
On homotopy types of 2-dimensional polyhedra
On J.H.C. Whitehead's aspherical question I.
On small geometric invariants of 3-manifolds.
On the absolute value of the SO(3)-invariant and other summands of the Turaev-Viro invariant
On the boundary of 2-dimensional ideal polyhedra
It is proved that for every two points in the visual boundary of the universal covering of a -dimensional ideal polyhedron, there is an infinity of paths joining them.
On the dimension of 2-dimensional Bestvina-Brady groups.
On the connectivity of skeletons of pseudomanifolds with boundary
In this note we show that -skeletons and -skeletons of -pseudomanifolds with full boundary are -connected graphs and -connected -complexes, respectively. This generalizes previous results due to Barnette and Woon.
On the Homeotopy Groups of Surfaces.
On the planarity of 2-complexes
On the Space of the Linear Homeomorphisms of a Polyhedral TV-Cell with Two Interior Vertices*.
One-relator groups and proper 3-realizability.
Optics in Croke-Kleiner Spaces
We explore the interior geometry of the CAT(0) spaces , constructed by Croke and Kleiner [Topology 39 (2000)]. In particular, we describe a diffraction effect experienced by the family of geodesic rays that emanate from a basepoint and pass through a certain singular point called a triple point, and we describe the shadow this family casts on the boundary. This diffraction effect is codified in the Transformation Rules stated in Section 3 of this paper. The Transformation Rules have various applications....