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## Examining the biological species steady-state density equation in spaces with different dimensions

Moscow University Computational Mathematics and Cybernetics. 2015. Vol. 39. No. 4. P. 157-162.

Bodrov A.G., Nikitin A. A.

A computational solution to the integral equation in the biological spatial model is found. The numerical techniques that are used (the Nystr{\"o}m and Neumann series methods, the latter being one of successive approximations) yield a reasonably accurate solution. An approach of moving from multidimensional equations to a one-dimensional equation for high-dimensional spaces is proposed. Explicit formulas for kernels when there are normal initial kernels are also proposed.

Nikitin A.A., Savost’yanov A. S., Moscow University Computational Mathematics and Cybernetics 2017 Vol. 41 No. 3 P. 122-129

The two-species model of self-structured stationary biological communities proposed by U. Dieckmann and R. Law is considered. A way of investigating the system of integro-differential equations describing the model equilibrium is developed, nontrivial stationary points are found, and constraints on the model parameter space resulting in similar stationary points are studied. The results are applied ...

Added: September 3, 2017

Nikitin A. A., Nikolaev M. V., Moscow University Computational Mathematics and Cybernetics 2018 Vol. 42 No. 3 P. 105-113

Integral equations emerging in a model of stationary biological communities such that their kernels have variable coefficients of excess (kurtosian kernels)are investigated. The dependence of the first and second spatial moment on the dimension of the environment is considered. A fastcomputation algorithm for the multi-dimensional nonlinear convolution is considered. The existence of a radial solution ...

Added: October 25, 2018

Nikitin A. A., Savost’yanov Anton Sergeevich, Moscow University Computational Mathematics and Cybernetics 2017 Vol. 41 No. 3 P. 122-129

The two-species model of self-structured stationary biological communities proposed by U. Dieckmann and R. Law is considered. A way of investigating the system of integro-differential equations describing the model equilibrium is developed, nontrivial stationary points are found, and constraints on the model parameter space resulting in similar stationary points are studied. The results are applied ...

Added: September 3, 2018

Гаджиев С. Р., Галкин Е. Г., Nikitin A. A., Вестник Московского университета. Серия 15: Вычислительная математика и кибернетика 2021 № 2 С. 11-18

This article explores nonlinear integral equation system that appears in the biological model of spatial stochastic population dynamics by U. Dieckmann and R. Law. We introduce the model and explain the reasoning behind using spatial moments within this model. We show derivation of nonlinear integral equation for equilibrium state after performing third degree closure on ...

Added: December 15, 2020

Николаев М. В., Nikitin A. A., Доклады Академии наук 2019 Т. 488 № 6 С. 595-598

В данной работе изучается нелинейное интегральное уравнение, возникшее в пространственной модели
биологических сообществ, разработанной австрийскими учёными Ульфом Дикманом и Ричардом Лоу.
Были найдены достаточные условия существования решения данного уравнения (неподвижной точки
интегрального оператора). Также изучен вопрос о единственности решения. ...

Added: November 7, 2019

Галкин Е. Г., Nikitin A. A., Вестник Московского университета. Серия 15: Вычислительная математика и кибернетика 2020 № 2 С. 11-18

The article presents the main approaches to the study of the stochastic process of population dynamics with continuous time and space and with fixed individuals, a countable system of integro-differential equations corresponding to the dynamics of spatial moments of this process is derived, and a method for finding an approximate solution using the method of ...

Added: February 18, 2020

Nikitin A. A., Nikolaev M. V., Differential Equations 2019 Vol. 55 No. 9 P. 1164-1173

We study a nonlinear integral equation arising from the parametric closure for the third spatial moment in the Dieckmann-Law model of stationary biological communities. The existence of a fixed point of the integral operator defined by this equation is analyzed. The noncompactness of the resulting operator is proved. Conditions are stated under which the equation ...

Added: November 7, 2019

Николаев М. В., Nikitin A. A., Дифференциальные уравнения 2019 Т. 55 № 9 С. 1209-1217

В работе изучается нелинейное интегральное уравнение, возникающее в результате параметрического замыкания третьего пространственного момента в модели У. Дикмана и Р. Лоу. Исследуется вопрос о существовании неподвижной точки интегрального оператора, задаваемого данным уравнением. Доказывается некомпактность полученного оператора. Формулируются условия, при которых уравнение имеет нетривиальное решение. ...

Added: November 7, 2019

Bodrov A.G., Nikitin A. A., Doklady Mathematics 2014 Vol. 89 No. 2 P. 210-213

Added: September 28, 2017

Nikitin A. A., International Journal of Open Information Technologies 2018 Т. 6 № 10 С. 1-8

This article is devoted to the mathematical formulation and numerical study of the spatial model of stationary biological communities by U. Dickman and R. Low. The main idea of this model is to find a "projection" of the simulated biological process on certain characteristics, the dynamics of which can be written analytically. Such "characteristics" in ...

Added: October 25, 2018

Kalistratova A., Nikitin A. A., Doklady Mathematics 2016 Vol. 94 No. 2 P. 574-577

In this paper, we study the integral equation that has arisen in the spatial model of stationary communities developed by Austrian scientists Ulf Dickman and Richard Low. A special case of this equation is considered with integral kernels, which are the Student’s distribution. The existence of a solution in this case is proved, and the ...

Added: December 8, 2016

Nikolaev M. V., Nikitin A. A., Doklady Mathematics 2019 Vol. 100 No. 2 P. 485-487

A nonlinear integral equation arising in the spatial model of biological communities developed by Austrian
scientists Ulf Dieckmann and Richard Law is studied. Sufficient conditions for the existence of a solution of
this equation (a fixed point of the integral operator) are found. The uniqueness of the solution is also analyzed. ...

Added: November 7, 2019

Гаджиев С. Р., Nikitin A. A., Современные информационные технологии и ИТ-образование 2019 Т. 15 № 2 С. 298-305

This article is devoted to the nonlinear integral equation arising in the biological model of Ulf Dieckmann and Richard Low. A brief review of the model of foreign authors Individual-based model is made, the meaning and necessity of introducing spatial moments is described. The following is the derivation of the nonlinear equation (for the equilibrium ...

Added: November 7, 2019

Decrouez G. G., Hall P., Bernoulli: a journal of mathematical statistics and probability 2013 Vol. 19 No. 4 P. 1268-1293

Motivated by a problem arising when analysing data from quarantine searches, we explore properties of distributions of sums of independent means of independent lattice-valued random variables. The aim is to determine the extent to which approximations to those sums require continuity corrections. We show that, in cases where there are only two different means, the ...

Added: September 29, 2014

Kotelnikova M. V., Aistov A., Вестник Нижегородского университета им. Н.И. Лобачевского. Серия: Социальные науки 2019 Т. 55 № 3 С. 183-189

The article describes a method that allows to improve the content of disciplines of the mathematical cycle by dividing them into invariant (general) and variable parts. The invariants were identified for such disciplines as «Linear algebra», «Mathematical analysis», «Probability theory and mathematical statistics» delivered to Bachelors program students of economics at several universities. Based on ...

Added: January 28, 2020

Danilov V., Rakhel M., Russian Journal of Mathematical Physics 2021 Vol. 28 No. 2 P. 179-187

In this paper, we show how to construct an asymptotic representation of the fundamental solution to the Cauchy problem for degenerate linear parabolic equations. ...

Added: June 6, 2021

Malyshev D., Alekseev V., Дискретный анализ и исследование операций 2008 Т. 15 № 1 С. 3-10

Доказывается полиномиальная разрешимость задачи о независимом множестве для бесконечного семейства подмножеств класса планарных графов. ...

Added: August 31, 2012

Akopov A. S., Beklaryan L. A., Saghatelyan A. K., Environmental Modelling and Software 2019 Vol. 116 P. 7-25

Urban greenery such as trees can effectively reduce air pollution in a natural and eco-friendly way. However, how to spatially locate and arrange greenery in an optimal way remains as a challenging task. We developed an agent-based model of air pollution dynamics to support the optimal allocation and configuration of tree clusters in a city. The Pareto ...

Added: February 24, 2019

Malyshev D., Journal of Applied and Industrial Mathematics 2020 Vol. 14 No. 4 P. 706-721

The edge coloring problem for a graph is to minimize the number of colors that are sufficient to color all edges of the graph so that all adjacent edges receive distinct colors. The computational complexity of the problem is known for all graph classes defined by forbidden subgraphs with at most 6 edges. We improve ...

Added: January 30, 2021

Lanham : University Press of America, 2012

The history of logic and analytic philosophy in Central and Eastern Europe is still known to very few people. As an exception to the rule, only two scientific schools became internationally popular: the Vienna Circle and the Lvov-Warsaw School. Nevertheless, the countries included in this region have not only joint history, but also joint cultural ...

Added: February 13, 2013

Chernyshev S. V., Cherepanov E. A., Pankratiev E. V. et al., Journal of Mathematical Sciences 2005 Vol. 128 No. 6 P. 3487-3495

Added: January 27, 2014

Decrouez G. G., Robinson A., Risk Analysis: An International Journal 2013 Vol. 33 No. 12 P. 2142-2153

We propose a new modeling approach for inspection data that provides a more useful interpretation of the patterns of detections of invasive pests, using cargo inspection as a motivating example. Methods that are currently in use generally classify shipments according to their likelihood of carrying biosecurity risk material, given available historical and contextual data. Ideally, ...

Added: September 29, 2014

P. : Université Paris 13 - Paris Sorbonne Cité, 2013

In this workshop we will bring together participants who have solutions for one or more of the following problems: How can mutual understanding be optimized with the help of technology in hospitals where both patients and professionals have varying language skills, cultural backgrounds and cognitive capacities? Can domain ontologies, natural language processing tools, multilingual knowledge-based ...

Added: December 18, 2014

Malyshev D., Discrete Mathematics 2015 Vol. 338 No. 11 P. 1860-1865

We completely determine the complexity status of the 3-colorability problem for hereditary graph classes defined by two forbidden induced subgraphs with at most five vertices. ...

Added: April 7, 2014