We consider the problem of separating two sets of points in an <i>n</i>-dimensional real space with a (hyper)plane that minimizes the sum of <i>L<sub>p</sub...

In this paper we develop a Variable neighborhood search (VNS) heuristic for solving Mixed-Integer Programs (MIP’s). It uses CPLEX, the general-purpose MIP s...

An upper bound is given on the variance of degrees of graphs with <i>n</i> vertices, <i>m</i> edges and maximum degree &Delta;. Particular cases of chemical...

The algebraic connectivity <i>a(G)</i> of a graph <i>G = (V,E)</i> is the second smallest eigenvalue of its Laplacian matrix. Using the AutoGraphiX (AGX) sys...

Chemical graphs, as other ones, are <i>regular</i> if all their vertices have the same degree. Otherwise, they are <i>irregular</i> and it is of interest to...

The uniting feature of combinatorial optimization and extremal graph theory is that in both areas one should &#64257;nd extrema of a function defined in most...

Conjectures in graph theory have multiple forms and involve graph invariants, graph classes, subgraphs, minors and other concepts in premisses and/or conclu...

Computer-assisted and automated conjecture-making in graph theory is reviewed, focusing on the three operational systems GRAPH, Graffiti and AutoGraphiX (AGX...

Two ways for bounding <i>n</i>-variables functions over a box, based on interval evalu- ations of first order derivatives, are compared. The optimal Baumann...

We consider the bilevel uncapacitated facility location problem with user preferences. It is known that this model may be reformulated as a one-level locati...

The multiprocessor scheduling problem with communication delays that we consider in this paper consists of finding a static schedule of an arbitrary task gra...

In this exploratory study, a segmentation analysis of a shopping mall’s customers is conducted according to the activities they performed during their visit,...

This paper examines the convergence properties of two well-known heuristics: variable neighborhood search (VNS) and random multistart local search (MLS). Bot...

When applying the 2-opt heuristic to the travelling salesman problem, selecting the best improvement at each iteration gives worse results on average than se...

The berth allocation problem is to allocate space along the quayside to incoming ship at a container terminal in order to minimize some objective function....

The berth allocation problem is to allocate berths (i.e., sections of the quayside) to ships arriving in a container port in order to minimize the sum of the...

Bimatrix and polymatrix games are expressed as parametric linear 0-1 programs. This leads to an algorithm for complete enumeration of their extreme equilibri...

Goal Programming with fractional objectives can be reduced to mathematical programming with a linear objective under linear and quadratic constraints, thus...

This paper answers a query of S. Vincze (Acta Univ. Szeged, Sect. Sci. Math. 12 A (1950) 136-142): find the convex octagon with unit-length sides and minim...

Variable Neighborhood Search (VNS) is a recent metaheuristic, or framework for building heuristics, which exploits systematically the idea of neighborhood ch...