Results 11 to 20 of about 1,025 (106)

Sparse graphs using exchangeable random measures. [PDF]

open access: yesJ R Stat Soc Series B Stat Methodol, 2017
Summary Statistical network modelling has focused on representing the graph as a discrete structure, namely the adjacency matrix. When assuming exchangeability of this array—which can aid in modelling, computations and theoretical analysis—the Aldous–Hoover theorem informs us that the graph is necessarily either dense or empty.
Caron F, Fox EB.
europepmc   +2 more sources

The stationary AKPZ equation: Logarithmic superdiffusivity

open access: yesCommunications on Pure and Applied Mathematics, Volume 76, Issue 11, Page 3044-3103, November 2023., 2023
Abstract We study the two‐dimensional Anisotropic KPZ equation (AKPZ) formally given by ∂tH=12ΔH+λ((∂1H)2−(∂2H)2)+ξ,$$\begin{equation*} \hspace*{3.4pc}\partial _t H=\frac{1}{2}\Delta H+\lambda ((\partial _1 H)^2-(\partial _2 H)^2)+\xi , \end{equation*}$$where ξ is a space‐time white noise and λ is a strictly positive constant.
Giuseppe Cannizzaro   +2 more
wiley   +1 more source

On the Su–Schrieffer–Heeger model of electron transport: Low‐temperature optical conductivity by the Mellin transform

open access: yesStudies in Applied Mathematics, Volume 151, Issue 2, Page 555-584, August 2023., 2023
Abstract We describe the low‐temperature optical conductivity as a function of frequency for a quantum‐mechanical system of electrons that hop along a polymer chain. To this end, we invoke the Su–Schrieffer–Heeger tight‐binding Hamiltonian for noninteracting spinless electrons on a one‐dimensional (1D) lattice.
Dionisios Margetis   +2 more
wiley   +1 more source

Continuous‐time multi‐type Ehrenfest model and related Ornstein–Uhlenbeck diffusion on a star graph

open access: yesMathematical Methods in the Applied Sciences, Volume 45, Issue 9, Page 5483-5512, June 2022., 2022
We deal with a continuous‐time Ehrenfest model defined over an extended star graph, defined as a lattice formed by the integers of d semiaxis joined at the origin. The dynamics on each ray are regulated by linear transition rates, whereas the switching among rays at the origin occurs according to a general stochastic matrix.
Antonio Di Crescenzo   +2 more
wiley   +1 more source

Bicomplex Landau and Ikehara Theorems for the Dirichlet Series

open access: yesJournal of Mathematics, Volume 2022, Issue 1, 2022., 2022
The aim of this paper is to generalize the Landau‐type Tauberian theorem for the bicomplex variables. Our findings extend and improve on previous versions of the Ikehara theorem. Also boundedness result for the bicomplex version of Ikehara–Korevaar theorem is derived.
Ritu Agarwal   +5 more
wiley   +1 more source

For Most Frequencies, Strong Trapping Has a Weak Effect in Frequency‐Domain Scattering

open access: yesCommunications on Pure and Applied Mathematics, Volume 74, Issue 10, Page 2025-2063, October 2021., 2021
It is well‐known that when the geometry and/or coefficients allow stable trapped rays, the outgoing solution operator of the Helmholtz equation grows exponentially through a sequence of real frequencies tending to infinity. In this paper we show that, even in the presence of the strongest possible trapping, if a set of frequencies of arbitrarily small ...
David Lafontaine   +2 more
wiley   +1 more source

Campana points of bounded height on vector group compactifications

open access: yesProceedings of the London Mathematical Society, Volume 123, Issue 1, Page 57-101, July 2021., 2021
Abstract We initiate a systematic quantitative study of subsets of rational points that are integral with respect to a weighted boundary divisor on Fano orbifolds. We call the points in these sets Campana points. Earlier work of Campana and subsequently Abramovich shows that there are several reasonable competing definitions for Campana points.
Marta Pieropan   +3 more
wiley   +1 more source

On the decoupled Markov group conjecture

open access: yesBulletin of the London Mathematical Society, Volume 53, Issue 1, Page 240-247, February 2021., 2021
Abstract The Markov group conjecture, a long‐standing open problem in the theory of Markov processes with countable state space, asserts that a strongly continuous Markov semigroup T=(Tt)t∈[0,∞) on ℓ1 has bounded generator if the operator T1 is bijective. Attempts to disprove the conjecture have often aimed at glueing together finite‐dimensional matrix
Jochen Glück
wiley   +1 more source

Optimal control of a large dam [PDF]

open access: yes, 2006
A large dam model is an object of study of this paper. The parameters $L^{lower}$ and $L^{upper}$ are its lower and upper levels, $L=L^{upper}-L^{lower}$ is large, and if a current level of water is between these bounds, then the dam is assumed to be in ...
Abdel-Hameed   +11 more
core   +7 more sources

Voronoi means, moving averages, and power series [PDF]

open access: yes, 2016
We introduce a {\it non-regular} generalisation of the N\"{o}rlund mean, and show its equivalence with a certain moving average. The Abelian and Tauberian theorems establish relations with convergent sequences and certain power series.
Bingham, N. H., Gashi, Bujar
core   +2 more sources

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