On a class of distributions stable under random summation

We investigate a family of distributions having a property of stability-under-addition, provided that the number $\nu$ of added-up random variables in the random sum is also a random variable. We call the corresponding property a \,$\nu$-stability and investigate the situation with the semigroup generated by the generating function of $\nu$ is commutative. Using results from the theory of iterations of analytic functions, we show that the characteristic function of such a $\nu$-stable distribution can be represented in terms of Chebyshev polynomials, and for the case of $\nu$-normal distribution, the resulting characteristic function corresponds to the hyperbolic secant distribution. We discuss some specific properties of the class and present particular examples.Comment: 12 pages, 1 figur

Absorption by Threebranes and the AdS/CFT Correspondence

In the first part of this talk I discuss two somewhat different supergravity approaches to calculating correlation functions in strongly coupled Yang-Mills theory. The older approach relates two-point functions to cross-sections for absorption of certain incident quanta by threebranes. In this approach the normalization of operators corresponding to the incident particles is fixed unambiguously by the D3-brane DBI action. By calculating absorption cross-sections of all partial waves of the dilaton we find corresponding two-point functions at strong `t Hooft coupling and show that they are identical to the weak coupling results. The newer approach to correlation functions relates them to boundary conditions in AdS space. Using this method we show that for a certain range of negative mass-squared there are two possible operator dimensions corresponding to a given scalar field in AdS, and indicate how to calculate correlation functions for either of these choices. In the second part of the talk I discuss an example of AdS/CFT duality which arises in the context of type 0 string theory. The CFT on N coincident electric and magnetic D3-branes is argued to be stable for sufficiently weak `t Hooft coupling. It is suggested that its transition to instability at a critical coupling is related to singularity of planar diagrams.Comment: 14 pages, LaTeX; Talk at Strings '99, Potsdam, German

Heavy-tailed probability distributions in social sciences

We present an overview of possible reasons for the appearance of heavy-tailed distributions in applications to the natural sciences. These distributions include the laws of Pareto, Lotka, and some new ones. The reasons are illustrated using suitable toy models. Keywords: heavy-tailed distributions; Pareto law; Lotka law; Zipf law; probability generating function

Cycle of the needs satisfaction, and information support of the society development simulation system

The report focuses on some of the key points of constructing a model of an artificial society. It is based on the processes of emergence and implementation of the needs of specific agents, depending on the internal processes in the agents, and external environmental factors. Unlike in other approaches, the basis of the modeled system agents' behavior is the concept of needs as the necessity of implementation of the agents' transition from one state to another. This article presents an algorithm of the needs satisfaction of the agent, starting with the event that caused the need for, and ending its satisfaction, or the message that it is impossible to satisfy. The basis of objective knowledge in the system are a model of active and passive agents, as well as recipes meet the needs of the active agents and the relationships between them. © 2017 Author(s)

Fuzzy spaces and new random matrix ensembles

We analyze the expectation value of observables in a scalar theory on the fuzzy two sphere, represented as a generalized hermitian matrix model. We calculate explicitly the form of the expectation values in the large-N limit and demonstrate that, for any single kind of field (matrix), the distribution of its eigenvalues is still a Wigner semicircle but with a renormalized radius. For observables involving more than one type of matrix we obtain a new distribution corresponding to correlated Wigner semicircles.Comment: 12 pages, 1 figure; version to appear in Phys. Rev.