Introduction 3 1. Affine geometry 4 1.1. Affine spaces 5 1.1.1. Euclidean geometry and its isometries 5 1.1.2. Affine spaces 7 1.1.3. Affine transformations 8 1.1.4. Tangent spaces 9 1.1.5. Acceleration and geodesics 10 1.1.6. Connections 11 1.2. The hierarchy of structures 11 1.3. Affine vector fields 12 1.4. Affine subspaces 13 1.5. Volume in affine geometry 14 1.6. Centers of gravity 14 1.7....

Given the n-dimensional space Fq , the elements of the projective spaces are all subspaces of Fq . Recently these codes have found application in error-correction of network coding. In this paper we examine a few interesting aspects of coding theory in projective spaces. We present codes and bounds in the projective spaces metric and prove that there are no perfect codes in this metric. We cons...

We consider the vanishing problem for higher cohomology groups on certain infinite-dimensional complex spaces: good branched coverings of suitable projective spaces and subvarieties with a finite free resolution in a projective space P(V ) (e.g. complete intersections or cones over finitedimensional projective spaces). In the former case we obtain the vanishing result for H. In the latter case ...

Spaces in the genus of infinite quaternionic projective space which admit essential maps from infinite complex projective space are classified. In these cases the sets of homotopy classes of maps are described explicitly. These results strengthen the classical theorem of McGibbon and Rector on maximal torus admissibility for spaces in the genus of infinite quaternionic projective space. An inte...

Finite point configurations in projective spaces are combinatorially described by matroids, where full (finite) projective spaces correspond to connected modular matroids. Every representable matroid can in fact be extended to a modular one. However, we show that some matroids do not even have a modularly complemented extension. Enlarging the class of “ambient spaces” under consideration, we sh...

In 1969 Buekenhout characterized non-singular quadrics of finite-dimensional projective spaces as polar spaces spanning the whole space and containing every line of the projective space which they intersect in at least three points (see [2]). Using suitable synthetic properties of the pairs of non-collinear disjoint lines, in this paper I present a new characterization of polar spaces and a com...

We construct projective moduli spaces for torsion-free sheaves on noncommutative projective planes. These moduli spaces vary smoothly in the parameters describing the noncommutative plane and have good properties analogous to those of moduli spaces of sheaves over the usual (commutative) projective plane P. The generic noncommutative plane corresponds to the Sklyanin algebra S = Skl(E,σ) constr...