Zobrazeno 1 - 10
of 227
pro vyhledávání: '"Sedaghat H"'
Autor:
Sedaghat, H.
We characterize all bounded orbits of two similar Collatz-type quadratic mappings of the set of non-negative integers. In one case, where cycles of all possible lengths may occur, an orbit is bounded if and only if it reaches a cycle. For the other m
Externí odkaz:
http://arxiv.org/abs/2004.07357
Autor:
Sedaghat, H.
For rings R with identity, we define a class of nonlinear higher order recurrences on unitary left R-modules that include linear recurrences as special cases. We obtain conditions under which a recurrence of order k+1 in this class is equivalent to a
Externí odkaz:
http://arxiv.org/abs/1706.07306
Autor:
Lazaryan, N., Sedaghat, H.
We study the evolution in discrete time of certain age-structured populations, such as adults and juveniles, with a Ricker fitness function. We determine conditions for the convergence of orbits to the origin (extinction) in the presence of the Allee
Externí odkaz:
http://arxiv.org/abs/1702.02889
Autor:
Sedaghat, H.
A general sufficient condition for the convergence of subsequences of solutions of non-autonomous, nonlinear difference equations and systems is obtained. For higher order equations the delay sizes and patterns play essential roles in determining whi
Externí odkaz:
http://arxiv.org/abs/1702.02884
Autor:
Lazaryan, N., Sedaghat, H.
Publikováno v:
Journal of Difference Equations and Applications (2016) 22, 1199-1223
We study the dynamics of the positive solutions of a second-order, Ricker-type exponential difference equation with periodic parameters. We find that qualitatively different dynamics occur depending on whether the period p of the main parameter is od
Externí odkaz:
http://arxiv.org/abs/1602.02138
Autor:
Lazaryan, N., Sedaghat, H.
Publikováno v:
Journal of Difference Equations and Applications (2016) 22, 519-544
We study the dynamics of a second-order difference equation that is derived from a planar Ricker model of two-stage (e.g. adult, juvenile) biological populations. We obtain sufficient conditions for global convergence to zero in the non-autonomous ca
Externí odkaz:
http://arxiv.org/abs/1509.08132
Autor:
Sedaghat, H.
Publikováno v:
Journal of Difference Equations and Applications, 21 (2015) 1-15
We discuss the method of folding for discrete planar systems and use it to establish the existence or non-existence of cycles or chaos in planar systems of rational difference equations with variable coefficients. These include some systems that conv
Externí odkaz:
http://arxiv.org/abs/1406.6721
Autor:
Lazaryan, N., Sedaghat, H.
By folding an autonomous system of rational equations in the plane to a scalar difference equation, we show that the rational system has coexisting periodic orbits of all possible periods as well as stable aperiodic orbits for certain parameter range
Externí odkaz:
http://arxiv.org/abs/1405.3124
Autor:
Sedaghat, H.
By folding nonautonomous differential systems in the plane to scalar differential equations, a sufficient condition for the non-occurrence of chaotic behavior is obtained.
Comment: 5 pages long
Comment: 5 pages long
Externí odkaz:
http://arxiv.org/abs/1405.2542
Autor:
Sedaghat, H.
A typical system of k difference (or differential) equations can be compressed, or folded into a difference (or ordinary differential) equation of order k. Such foldings appear in control theory as the canonical forms of the controllability matrices.
Externí odkaz:
http://arxiv.org/abs/1403.3995