arXiv subjects

E. Braverman

Publications and source records attributed to E. Braverman.

7 recordsLinked to original sources

arXiv2016

Competitive-cooperative models with various diffusion strategies

The paper is concerned with different types of dispersal chosen by competing species. We introduce a model with the diffusion-type term $\nabla \cdot \left[ a \nabla \left( u/P \right) \right]$ which includes some previously studied systems as special cases, where a positive space-dependent function $P$ can be interpreted as a chosen dispersal strategy. The well-known result that if the first species chooses $P$ proportional to the carrying capacity while the second does not then the first species will bring the second one to extinction, is also valid for this type of dispersal. However, we focus on the case when the ideal free distribution is attained as a combination of the two strategies adopted by the two species. Then there is a globally stable coexistence equilibrium, its uniqueness is justified. If both species choose the same dispersal strategy, non-proportional to the carrying capacity, then the influence of higher diffusion rates is negative, while of higher intrinsic growth rates is positive for survival in a competition. This extends the result of [J. Math. Biol. {\bf 37} (1) (1998), 61--83] for the regular diffusion to a more general type of dispersal.

math.DS↗

arXiv1995

Impulsive Stabilization of Linear Delay Differential Equations

The paper is concerned with stabilization of a scalar delay differention equation $$ {\dot x}(t) - \sum_{k=1}^m A_k(t)x[h_k(t)] = 0,~t\geq 0,~ x(ξ)=φ(ξ), ξ<0, $$ by introducing impulses in certain moments of time $$ x(τ_j) = B_j x(τ_j -0), ~j=1,2, \dots ~. $$ Explicit stability results are presented both for the equation with positive coefficients and for the equation with $A_k$ being of arbitrary sign.

funct-an↗

arXiv1995

Oscillation of a Linear Delay Impulsive Differential Equation

The main result of the paper is that the oscillation (non-oscillation) of the impulsive delay differential equation $\dot {x}(t)+\sum_{k=1}^m A_k(t)x[h_k(t)]=0,~~t\geq 0$, $x(τ_j)=B_jx(τ_j-0), \lim τ_j = \infty$ is equivalent to the oscillation (non-oscillation) of the equation without impulses $\dot {x}(t)=\sum_{k=1}^m A_k(t) \prod_{h_k(t)<τ_j\leq t} B_j^{-1}x[h_k(t)]=0, t \geq 0$. Explicit oscillation results are presented.

funct-an↗

arXiv1994

On Integrable Solutions of Impulsive Delay Differential Equations

The connection of function properties of solutions with exponential stability of linear impulsive differential equation $$\dot{x} (t) - \sum_{k=1}^m {A_k (t) x[h_k(t)]} = r(t),~ t \geq 0, x(ξ) = φ(ξ),~ ξ< 0,$$ $$x(τ_j) = B_j x(τ_j - 0) , ~j=1,2, \dots .$$ The explicit stability results and sufficient conditions for existence of integrable solutions are presented.

funct-an↗

arXiv1994

Boundedness and Stability of Impulsively Perturbed Delay Differential Equations

Suppose any solution of a linear impulsive delay differential equation $$ \dot{x} (t) + \sum_{i=1}^m A_i (t) x[h_i (t)] = 0,~t \geq 0, x(s) = 0, s < 0, $$ $$ x(τ_j +0) = B_j x(τ_j -0) + α_j, ~j=1,2, ... ,$$ is bounded for any bounded sequence $\{ α_i \}$. The conditions ensuring exponential stability of this equation are presented. The behavior of solutions of the non-homogeneous equation is analyzed.

funct-an↗

arXiv1993

Boundedness and Stability of Impulsively Perturbed Systems in a Banach Space

Consider a linear impulsive equation in a Banach space $$\dot{x}(t)+A(t)x(t) = f(t), ~t \geq 0,$$ $$x(τ_i +0)= B_i x(τ_i -0) + α_i,$$ with $\lim_{i \rightarrow \infty} τ_i = \infty $. Suppose each solution of the corresponding semi-homogeneous equation $$\dot{x}(t)+A(t)x(t) = 0,$$ (2) is bounded for any bounded sequence $\{ α_i \}$. The conditions are determined ensuring (a) the solution of the corresponding homogeneous equation has an exponential estimate; (b) each solution of (1),(2) is bounded on the half-line for any bounded $f$ and bounded sequence $\{ α_i \}$ ; (c) $\lim_{t \rightarrow \infty}x(t)=0$ for any $f, α_i$ tending to zero; (d) exponential estimate of $f$ implies a similar estimate for $x$.

funct-an↗

arXiv1993

Exponential Stability of Linear Delay Impulsive Differential Equations

For ordinary differential equations and functional differential equations the following result is well known. Suppose any solution is bounded on the half-line for each bounded on the half-line right-hand side. Then under certain conditions the equations is exponentially stable. We prove the same result for a delay differential equation $$ \dot{x}(t) + \sum_{i=1}^k A_i (t)x[h_i(t)] = f(t), $$ with impulses $$ x(τ_i + 0) = B_i x(τ_i - 0) $$ at fixed moments $τ_i$. The proof is based on a solution representation formula obtained here.

funct-an↗