For the p-median problem we study complexity of finding a local minimum in the worst and the average cases. We introduce several neighborhoods and show that the corresponding local search problems are PLS-complete. In the average case we note that standard local descent algorithm is polynomial. A relationship between local optima and 0–1 local saddle points is presented.

Previous analyses of the Earth’s annual cycle and its trends have utilized surface temperature data sets. Here we introduce a new analysis of the global and hemispheric annual cycle using a satellite remote sensing derived data set during the period 1979–2009, as determined from the lower tropospheric (LT) channel of the MSU satellite. While the surface annual cycle is tied directly to the heat...

Earlier investigations [1] showed local minima in the monopole-antimonopole potential in U(1) gauge theory on the lattice. In this paper we localize monopoles of Monte-Carlo configurations. A statistical analysis of localization measurements gives us the probability density which we compare with the potential found in [1]. We find the monopoles mainly located either in the center of three-dimen...

We compare two forms of hybrid genetic search. The rst uses Lamarckian evolution, while the second uses a related method where local search is employed to change the tness of strings, but the acquired improvements do not change the genetic encoding of the individual. The latter search method exploits the Baldwin eeect. By modeling a simple genetic algorithm we show that functions exist where si...

A maximum stable set in a graph G is a stable set of maximum cardinality. S is a local maximum stable set if it is a maximum stable set of the subgraph of G spanned by S ∪N(S), where N(S) is the neighborhood of S. One theorem of Nemhauser and Trotter Jr. [10], working as a useful sufficient local optimality condition for the weighted maximum stable set problem, ensures that any local maximum st...

Abstract. We use the Local Optima Network model to study the structure of symmetric TSP fitness landscapes. The ‘big-valley’ hypothesis holds that for TSP and other combinatorial problems, local optima are not randomly distributed, instead they tend to be clustered around the global optimum. However, a recent study has observed that, for solutions close in evaluation to the global optimum, this...