Short lists with short programs in short time - a short proof

Bauwens, Mahklin, Vereshchagin and Zimand [ECCC TR13-007] and Teutsch [arxiv:1212.6104] have shown that given a string x it is possible to construct in polynomial time a list containing a short description of it. We simplify their technique and present a shorter proof of this result

Evolution and models for skewed parton distributions

We discuss the structure of the ``forward visible'' (FW) parts of double and skewed distributions related to usual distributions through reduction relations. We use factorized models for double distributions (DDs) f(x, alpha) in which one factor coincides with the usual (forward) parton distribution and another specifies the profile characterizing the spread of the longitudinal momentum transfer. The model DDs are used to construct skewed parton distributions (SPDs). For small skewedness, the FW parts of SPDs H(x, xi) can be obtained by averaging forward parton densities f(x- xi alpha) with the weight rho (alpha) coinciding with the profile function of the double distribution f(x, alpha) at small x. We show that if the x^n moments f_n (alpha) of DDs have the asymptotic (1-alpha^2)^{n+1} profile, then the alpha-profile of f (x,alpha) for small x is completely determined by small-x behavior of the usual parton distribution. We demonstrate that, for small xi, the model with asymptotic profiles for f_n (alpha) is equivalent to that proposed recently by Shuvaev et al., in which the Gegenbauer moments of SPDs do not depend on xi. We perform a numerical investigation of the evolution patterns of SPDs and gave interpretation of the results of these studies within the formalism of double distributions.Comment: 24 pages, Latex, 12 figure

Power-Law Wave Functions and Generalized Parton Distributions for Pion

We propose a model for generalized parton distributions of the pion based on the power-law ansatz for the effective light-cone wave function.Comment: 27 pages, Latex; Revised and Extended Version, to be published in Phys. Rev.

Signs of crossing by the moon of the earth's magnetosphere tail according to data of charged particle traps on the first artificial satellite of the moon /Luna-10/

Space probe charged particle data evidence for moon crossing of Earth magnetospheric tai

On Algorithmic Statistics for space-bounded algorithms

Algorithmic statistics studies explanations of observed data that are good in the algorithmic sense: an explanation should be simple i.e. should have small Kolmogorov complexity and capture all the algorithmically discoverable regularities in the data. However this idea can not be used in practice because Kolmogorov complexity is not computable. In this paper we develop algorithmic statistics using space-bounded Kolmogorov complexity. We prove an analogue of one of the main result of `classic' algorithmic statistics (about the connection between optimality and randomness deficiences). The main tool of our proof is the Nisan-Wigderson generator.Comment: accepted to CSR 2017 conferenc

Gale–Nikaido–Debreu and Milgrom–Shannon: Communal interactions with endogenous community structures

© 2016 Elsevier Inc.This paper examines Nash jurisdictional stability in a model with a continuum of agents whose characteristics are distributed over a unidimensional interval. Communal benefits and costs of each individual depend on her identity and the composition of the community which she belongs to. Since the framework is too general to yield an existence of Nash equilibrium, we introduce the essentiality of membership in one of the communities for all individuals. We highlight the Border Indifference Property (BIP), when all individuals located on a border between two adjacent jurisdictions are indifferent about joining either of them and show that BIP is a necessary condition for yielding a Nash equilibrium. We invoke the celebrated Gale–Nikaido–Debreu Lemma to guarantee the existence of a partition that satisfies BIP. We then proceed to demonstrate that BIP is not sufficient to yield a Nash equilibrium. The equilibrium existence under BIP is rescued when we use the Milgrom–Shannon monotone comparative statics conditions

Non-local anomaly of the axial-vector current for bound states

We demonstrate that the amplitude $<\rho\gamma|\partial_\nu (\bar q\gamma_\nu \gamma_5 q)|0>$ does not vanish in the limit of zero quark masses. This represents a new kind of violation of the classical equation of motion for the axial current and should be interpreted as the axial anomaly for bound states. The anomaly emerges in spite of the fact that the one loop integrals are ultraviolet-finite as guaranteed by the presence of the bound-state wave function. As a result, the amplitude behaves like $\sim 1/p^2$ in the limit of a large momentum $p$ of the current. This is to be compared with the amplitude $$ which remains finite in the limit $p^2\to\infty$. The observed effect leads to the modification of the classical equation of motion of the axial-vector current in terms of the non-local operator and can be formulated as a non-local axial anomaly for bound states.Comment: revtex, 4 pages, numerical value for $\kappa$ in Eq. (19) is corrected, Eqs. (22) and (23) are modified. New references added. Results remain unchange

Regge Behavior of DIS Structure Functions

Building on previous works of the mid 1960's, we construct an integral equation for forward elastic scattering (t=0) at arbitrary virtuality Q^2 and large s=W^2. This equation sums the ladder production of massless intermediate bosons to all orders, and the solution exhibits Regge behavior. The equation is used to study scattering in a simple chi^2 phi scalar theory, where it is solved appoximately and applied to the study of DIS at small x. We find that the model can naturally describe the quark distribution in both the large x region and the small x region dominated by Reggeon exchange.Comment: 13 pages with 5 figure