We establish new lower bounds on the pair covering number Cλ(v, k) for infinitely many values of v, k and λ, including infinitely many values of v and k for λ = 1. Here, Cλ(v, k) denotes the minimum number of k-subsets of a v-set of points such that each pair of points occurs in at least λ of the k-subsets. We use these results to prove simple numerical conditions which are both necessary and s...

We investigate the Ramsey theory of continuous graph-structures on complete, separable metric spaces and apply the results to the problem of covering a plane by functions. Let the homogeneity number hm(c) of a pair-coloring c : [X]2 → 2 be the number of c-homogeneous subsets of X needed to cover X. We isolate two continuous pair-colorings on the Cantor space 2ω , cmin and cmax, which satisfy hm...

We investigate the covering problem in RT spaces induced by the RosenbloomTsfasman metric, extending the classical covering problem in Hamming spaces. Some connections between coverings in RT spaces and coverings in Hamming spaces are derived. Several lower and upper bounds are established for the smallest cardinality of a covering code in an RT space, generalizing results by Carnielli, Chen an...

In 1914 Lebesgue defined a ‘universal covering’ to be a convex subset of the plane that contains an isometric copy of any subset of diameter 1. His challenge of finding a universal covering with the least possible area has been addressed by various mathematicians: Pál, Sprague and Hansen have each created a smaller universal covering by removing regions from those known before. However, Hansen’...

Our main observation concerns closed geodesics on surfaces M with a smooth Finsler metric, i.e. a function F : TM → [0,∞) which is a norm on each tangent space TpM , p ∈ M , which is smooth outside of the zero section in TM , and which is strictly convex in the sense that Hess(F ) is positive definite on TpM \ {0}. One calls a Finsler metric F symmetric if F (p,−v) = F (p, v) for all v ∈ TpM . ...

In this paper we investigate the spectral problem in Finsler geometry. Due to nonlinearity of Finsler–Laplacian operator, introduce faithful dimension pairs by means which spectrum a compact reversible metric measure manifold is defined. Various upper and lower bounds such eigenvalues are provided spirit Cheng, Buser Gromov, extend several aspects results Hassannezhad, Kokarev Polterovich. More...