Asymptotics of a linear delay integral equation

In summary, the researcher is trying to find the asymptotic solutions to an equation that has a kernel that is different than what he currently has. He has been unsuccessful so far in finding a reference that can help him with this.
  • #1
Mute
Homework Helper
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Hello all,

During the course of a calculation I was doing for my research, I derived a delay integral equation of the form

[tex]g(x) = \int_0^1 dy K(y,x)g(x-y)[/tex]
where K(x,y) is a known, but somewhat ugly, kernel that has a [itex](1-y^2)^{-1/2}[/itex] singularity, but is integrable such that [itex]\int_0^1 dy K(y,x) = 1[/itex]. K is really a probability density function [itex]\rho(t;C)[/itex], where t is the variable and C is a parameter, and [itex]K(y,x) = \rho(y;a + (x-y)b)[/itex] . This also has the property that [itex]\rho(0;C) = 0[/itex].

g(x) is also interpretable as a probability distribution, so it should have the normalization [itex]\int_0^\infty dx g(x) = 1[/itex]

Although solving this equation exactly would be fantastic, what I would really like is to obtain the large x asymptotics of this equation. (g = 0 or 1 are obviously solutions of the integral equation, but fail to satisfy the normalization condition).

I tried assuming a functional relation [itex]g(x - y) = g(x)/K(y,x)[/itex], which solves the integral equation and leaves me with a functional equation to solve. Setting y = 0 in the equation, however, demonstrates that this can't be a solution because K(0,x) vanishes.

I have so far been unable to find any good references that might help find the asymptotic solution to this. Most of the delay integral equation papers I've found are either searching for forced periodic solutions, specific nonlinear integrands or very mathematical papers that show existence, uniqueness, stability, etc, but don't give me any clue on how I might solve it.

Does anyone here know of any good references that might help me solve for at least the large x asymptotics of such an equation?

Thanks.
 
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  • #2
Can you give a bit more information? Like exact form of K(x,y)? And the asymptotic behavior of K(x,y)?
 
  • #3
It turns out that I made an incorrect assumption in the derivation of this integral equation, so the true kernel is different than what I currently have, and I don't even know if I will still get an equation of this form if I were to fix the calculation.

So, for now, this topic can be disregarded, though I still welcome references on obtaining asymptotic solutions to integral equations.
 

FAQ: Asymptotics of a linear delay integral equation

1. What is an asymptotic analysis of a linear delay integral equation?

An asymptotic analysis of a linear delay integral equation involves studying the behavior of the solution of the equation as the independent variable approaches a certain limit, often infinity. This allows us to understand the long-term behavior of the solution and make approximations or predictions.

2. What is a linear delay integral equation?

A linear delay integral equation is an equation in which the unknown function appears both inside and outside of an integral. It also includes a delay term, which involves the value of the unknown function at a previous time. These types of equations often arise in the study of time-dependent processes.

3. What is the significance of studying asymptotics in linear delay integral equations?

Studying the asymptotics of a linear delay integral equation allows us to gain insight into the behavior of the solution in the long term. This can help us understand the stability and convergence of the solution, as well as make approximations or predictions about the behavior of the system.

4. What are some applications of linear delay integral equations?

Linear delay integral equations have many applications in various fields such as physics, engineering, and biology. They are often used to model time-dependent processes, such as population dynamics, chemical reactions, and heat transfer. They can also be used in control theory and signal processing.

5. What are some techniques used in analyzing asymptotics of linear delay integral equations?

Some common techniques used in the analysis of asymptotics in linear delay integral equations include Laplace transforms, Fourier transforms, and perturbation methods. These techniques help to simplify the equations and make them more manageable, allowing us to study the long-term behavior of the solution.

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