A contribution to the light field theory
A dyadic view of rational convex sets
Let be a subfield of the field of real numbers. Equipped with the binary arithmetic mean operation, each convex subset of becomes a commutative binary mode, also called idempotent commutative medial (or entropic) groupoid. Let and be convex subsets of . Assume that they are of the same dimension and at least one of them is bounded, or is the field of all rational numbers. We prove that the corresponding idempotent commutative medial groupoids are isomorphic iff the affine space ...
A general approach to dual characterizations of solvability of inequality systems with applications.
A general notion of extreme subset
A methodologically pure proof of a convex geometry problem.
A second order -approximation method for constrained optimization problems involving second order invex functions
A new approach for obtaining the second order sufficient conditions for nonlinear mathematical programming problems which makes use of second order derivative is presented. In the so-called second order -approximation method, an optimization problem associated with the original nonlinear programming problem is constructed that involves a second order -approximation of both the objective function and the constraint function constituting the original problem. The equivalence between the nonlinear...
Axiomatization and undecidability results for linear betweenness relations
Carathéodory's and Helly's dimensions of products of convexity structures
Compactness and countable compactness in weak topologies
A bounded closed convex set K in a Banach space X is said to have quasi-normal structure if each bounded closed convex subset H of K for which diam(H) > 0 contains a point u for which ∥u-x∥ < diam(H) for each x ∈ H. It is shown that if the convex sets on the unit sphere in X satisfy this condition (which is much weaker than the assumption that convex sets on the unit sphere are separable), then relative to various weak topologies, the unit ball in X is compact whenever it is countably compact....
Convexity on unions of sets
Convexity structures in zero-dimensional compact spaces.
Convexity theories 0 fin. Foundations.
In this paper we study big convexity theories, that is convexity theories that are not necessarily bounded. As in the bounded case (see [4]) such a convexity theory Γ gives rise to the category ΓC of (left) Γ-convex modules. This is an equationally presentable category, and we prove that it is indeed an algebraic category over Set. We also introduce the category ΓAlg of Γ-convex algebras and show that the category Frm of frames is isomorphic to the category of associative, commutative, idempotent...
Decomposability of Abstract and Path-Induced Convexities in Hypergraphs
An abstract convexity space on a connected hypergraph H with vertex set V (H) is a family C of subsets of V (H) (to be called the convex sets of H) such that: (i) C contains the empty set and V (H), (ii) C is closed under intersection, and (iii) every set in C is connected in H. A convex set X of H is a minimal vertex convex separator of H if there exist two vertices of H that are separated by X and are not separated by any convex set that is a proper subset of X. A nonempty subset X of V (H) is...
Dimension of convex hyperspaces
Dimension of convex hyperspaces : nonmetric case
Efficiency and Duality in Nonsmooth Multiobjective Fractional Programming Involving η-pseudolinear Functions
Eigenschaften offener und affiner Mengen in Verbandsstrukturen
Einige geometrische Aspekte der Bildverarbeitung
Equality of the Lebesgue and the inductive dimension functions for compact spaces with a uniform convexity
Errata to the paper "Families of convex sets closed under intersection, homotheties and uniting increasing sequences of sets" Fundamenta Mathematicae 120 (1984), pp. 14-40