The emergence of kinship behavior in structured populations of unrelated individuals

The paper provides an explanation for altruistic behavior based on the matching and learning technology in the population. In a infinite structured population, in which individuals meet and interact with their neighbors, individuals learn by imitating their more successful neighbors. We ask which strategies are robust against invasion of mutants: A strategy is unbeatable if when all play it and a finite group of identical mutants enters then the learning process eliminates the mutants with probability 1. We find that such an unbeatable strategy is necessarily one in which each individual behaves as if he is related to his neighbors and takes into account their welfare as well as his. The degree to which he cares depends on the radii of his neighborhoods. Received June 1996/Revised version October 1998     

Coulomb blockade as a probe for non-Abelian statistics in Read-Rezayi states

We consider a quantum dot in the regime of the quantum Hall effect, particularly in Laughlin states and non-Abelian Read-Rezayi states. We find the location of the Coulomb blockade peaks in the conductance as a function of the area of the dot and the magnetic field. When the magnetic field is fixed and the area of the dot is varied, the peaks are equally spaced for the Laughlin states. In contrast, non-Abelian statistics is reflected in modulations of the spacing which depend on the magnetic field.     

Biological control of fungal pathogens

Biological control of soil-borne plant pathogens is a potential alternative to the use of chemical pesticides, which have already been proved to be harmful to the environment. Several strains of the fungusTrichoderma have been isolated and found to be effective biocontrol agents of various soil-borne plant pathogenic fungi under greenhouse and field conditions. Different application approaches have been used including integration ofTrichoderma with reduced doses of chemical agents. Biochemical and molecular biology studies carried out to explore the mechanisms involved in biological control revealed thatTrichoderma is a rather specific mycoparasite. Lectins were found to be involved in the recognition betweenTrichoderma and its host fungi, whereas chitinase is involved in the degradation of the host cell wall. Genetic engineering techniques were employed in order to increase the effectiveness, stability, and biocontrol capacity ofTrichoderma spp. as well as other biocontrol agents, such asPseudomonass spp. andRhizobium.     

Computing in fault tolerant broadcast networks and noisy decision trees

We consider a fault tolerant broadcast network of n processors each holding one bit of information. The goal is to compute a given Boolean function on the n bits. In each step, a processor may broadcast one bit of information. Each listening processor receives the bit that was broadcast with error probability bounded by a fixed constant ?. The errors in different steps, as well as for different receiving processors in the same step, are mutually independent. The protocols that are considered in this model are oblivious protocols: At each step, the processors that broadcast are fixed in advanced and independent of the input and the outcome of previous steps. We present here the first linear complexity protocols for several classes of Boolean functions. This answer an open question of Yao (Invited talk in the 5th ISTCS Conf., 1997), considering this fault tolerant model that was introduced by El Gamal (Open problems presented at the 1984 workshop on Specific Problems in Communication and Computation sponsored by Bell Communication Research) and studied also by Gallager 10 . © 2008 Wiley Periodicals, Inc. Random Struct. Alg., 2009     

Testing for forbidden order patterns in an array

A sequence contains a pattern , that is, a permutations of [k], iff there are indices i₁ < … < i_k, such that f(i_x) > f(i_y) whenever π(x) > π(y). Otherwise, f is π‐free. We study the property testing problem of distinguishing, for a fixed π, between π‐free sequences and the sequences which differ from any π‐free sequence in more than ? n places. Our main findings are as follows: (1) For monotone patterns, that is, π = (k,k ? 1,…,1) and π = (1,2,…,k), there exists a nonadaptive one‐sided error ?‐test of query complexity. For any other π, any nonadaptive one‐sided error test requires queries. The latter lower‐bound is tight for π = (1,3,2). For specific it can be strengthened to Ω(n^{1 ? 2/(k + 1)}). The general case upper‐bound is O(?^?1/kn^{1 ? 1/k}). (2) For adaptive testing the situation is quite different. In particular, for any there exists an adaptive ?‐tester of query complexity.