arXiv subjects

Dmitry Panchenko

Publications and source records attributed to Dmitry Panchenko.

60 records · Page 4Linked to original sources

arXiv2004

Symmetrization approach to concentration inequalities for empirical processes

We introduce a symmetrization technique that allows us to translate a problem of controlling the deviation of some functionals on a product space from their mean into a problem of controlling the deviation between two independent copies of the functional. As an application we give a new easy proof of Talagrand's concentration inequality for empirical processes, where besides symmetrization we use only Talagrand's concentration inequality on the discrete cube {-1,+1}^n. As another application of this technique we prove new Vapnik-Chervonenkis type inequalities. For example, for VC-classes of functions we prove a classical inequality of Vapnik and Chervonenkis only with normalization by the sum of variance and sample variance.

math.PR↗

arXiv2004

Deviation inequality for monotonic Boolean functions with application to a number of k-cycles in a random graph

Using Talagrand's concentration inequality on the discrete cube {0,1}^m we show that given a real-valued function Z(x)on {0,1}^m that satisfies certain monotonicity conditions one can control the deviations of Z(x) above its median by a local Lipschitz norm of Z(x) at the point x. As one application, we give a simple proof of a nearly optimal deviation inequality for the number of k-cycles in a random graph.

math.PR↗

arXiv2004

Bounds for diluted mean-fields spin glass models

In an important recent paper, \cite{FL}, S. Franz and M. Leone prove rigorous lower bounds for the free energy of the diluted $p$-spin model and the $K$-sat model at any temperature. We show that the results for these two models are consequences of a single general principle. Our calculations are significantly simpler than those of \cite{FL}, even in the replica-symmetric case.

math.PR↗

arXiv2004

A central limit theorem for weighted averages of spins in the high temperature region of the Sherrington-Kirkpatrick model

In this paper we prove that in the high temperature region of the Sherrington-Kirkpatrick model for a typical realization of the disorder the weighted average of spins $\sum_{i\leq N} t_i σ_i$ will be approximately Gaussian provided that $\max_{i\leq N}|t_i|/\sum_{i\leq N} t_i^2$ is small.

math.PR↗

arXiv2004

A note on the free energy of the coupled system in the Sherrington-Kirkpatrick model

In this paper we consider a system of spins that consists of two configurations $\vsi^1,\vsi^2\inΣ_N=\{-1,+1\}^N$ with Gaussian Hamiltonians $H_N^1(\vsi^1)$ and $H_N^2(\vsi^2)$ correspondingly, and these configurations are coupled on the set where their overlap is fixed $\{R_{1,2}=N^{-1}\sum_{i=1}^N σ_i^1σ_i^2 = u_N\}.$ We prove the existence of the thermodynamic limit of the free energy of this system given that $\lim_{N\to\infty}u_N = u\in[-1,1]$ and give the analogue of the Aizenman-Sims-Starr variational principle that describes this limit via random overlap structures.

math.PR↗

arXiv2004

Rademacher processes and bounding the risk of function learning

We construct data dependent bounds on the risk in function learning problems. The bounds are based on the local norms of the Rademacher process indexed by the underlying function class and they do not require prior knowledge about the distribution of the training examples or any specific properties of the function class.

math.PR↗