On some classes of curves in a projective space
Let V be an origin-symmetric convex body in , n≥ 2, of Gaussian measure . It is proved that for every choice of vectors in the Euclidean unit ball , there exist signs with . The method used can be modified to give simple proofs of several related results of J. Spencer and E. D. Gluskin.
Let X be a set, κ be a cardinal number and let ℋ be a family of subsets of X which covers each x ∈ X at least κ-fold. What assumptions can ensure that ℋ can be decomposed into κ many disjoint subcovers? We examine this problem under various assumptions on the set X and on the cover ℋ: among other situations, we consider covers of topological spaces by closed sets, interval covers of linearly ordered sets and covers of ℝⁿ by polyhedra and by arbitrary convex sets. We focus on...
We give an example of a set of points in such that, for any partition of into triples, there exists a line stabbing of the triangles determined by the triples.