On the lower bound of packing density for convex bodies in the plane.
Motivated by the study of multidimensional control problems of Dieudonné-Rashevsky type, we raise the question how to understand to notion of quasiconvexity for a continuous function f with a convex body K instead of the whole space as the range of definition. In the present paper, we trace the consequences of an infinite extension of f outside K, and thus study quasiconvex functions which are allowed to take the value +∞. As an appropriate envelope, we introduce and investigate the lower semicontinuous...
The measurable sets of pairs of intersecting non-isotropic straight lines of type and the corresponding densities with respect to the group of general similitudes and some its subgroups are described. Also some Crofton-type formulas are presented.
We study the measurability of sets of pairs of straight lines with respect to the group of motions in the simply isotropic space by solving PDEs. Also some Crofton type formulas are obtained for the corresponding densities.
We study the maximum possible number of intersections of the boundaries of a simple -gon with a simple -gon in the plane for . To determine the number is quite easy and known when or is even but still remains open for and both odd. We improve (for ) the easy upper bound to and obtain exact bounds for