On the geometry of symplectic involutions.
On the graphs of Hoffman-Singleton and Higman-Sims.
On the Group of Transformations of Constructible Euclidean Planes with Preserve a Single Distance.
On the Haagerup inequality and groups acting on -buildings
Let be a group endowed with a length function , and let be a linear subspace of . We say that satisfies the Haagerup inequality if there exists constants such that, for any , the convolutor norm of on is dominated by times the norm of . We show that, for , the Haagerup inequality can be expressed in terms of decay of random walks associated with finitely supported symmetric probability measures on . If is a word length function on a finitely generated group , we show that,...
On the history of generalized quadrangles.
On the Impossibility of one Ruler-and-Compass Construction
On the incidence structures of polar spaces and quadrics.
On the Infinite Loch Ness monster
In this paper we introduce the topological surface called {Infinite Loch Ness monster}, discussing how this name has evolved and how it has been historically understood. We give two constructions of this surface, one of them having translation structure and the other hyperbolic structure.
On the integral geometry of the linear subspaces in a biplanar space
On the integration theorem for Lie groupoids
On the interpoint distance sum inequality.
On the iso-taxicab trigonometry.
On the Lifshits Constant for Hyperspaces
The Lifshits theorem states that any k-uniformly Lipschitz map with a bounded orbit on a complete metric space X has a fixed point provided k < ϰ(X) where ϰ(X) is the so-called Lifshits constant of X. For many spaces we have ϰ(X) > 1. It is interesting whether we can use the Lifshits theorem in the theory of iterated function systems. Therefore we investigate the value of the Lifshits constant for several classes of hyperspaces.
On the linearity of higher-dimensional blocking sets.
On the loop inequality for euclidean buildings
We give an estimate for the number of closed loops of given length in the 1-skeleton of a thick euclidean building. This kind of estimate can be used to prove the (RD) property for the subspace of radial functions on groups, as shown in the paper by A. Valette [same issue].
On the matrices of central linear mappings
We show that a central linear mapping of a projectively embedded Euclidean -space onto a projectively embedded Euclidean -space is decomposable into a central projection followed by a similarity if, and only if, the least singular value of a certain matrix has multiplicity . This matrix is arising, by a simple manipulation, from a matrix describing the given mapping in terms of homogeneous Cartesian coordinates.
On the Newton Polygon.
On the Non-Euclidian Geometry
On the non-existence of certain hyperovals in dual André planes of order 2.
On the Non-Existence of Certain M.D.S. Codes and Projective Planes.