# Math Help - Semilinear Wave Equation - White Noise

1. ## Semilinear Wave Equation - White Noise

Hello!

I am required to do a paper on the Semilinear Wave Equation as part of a Stochastic Partial Differential Equations seminar.
The problem is, that I've never taken a course on partial differential equations (only ordinary differential equations) or functional analysis.

Now I have the following in front of me:

Let $f(s,x,t)$ and $\sigma(s,x,t)$ be predictable random fields
depending on the parameters $s\in\mathbf{R}$ and $x\in D$. We consider
the initial-boundary value problems for a stochastic wave equation
as follows

$\frac{\partial^{2}u}{\partial t^{2}}=(\kappa\Delta-\alpha)u+f(u,x,t)+\dot{M}(u,x,t)$
$x\in D$, $t\in(0,T]$

$Bu$| $_{\partial D}=0$

$u(x,0)=g(x),$ $\frac{\partial u}{\partial t}(x,0)=h(x)$

where

$\dot{M}(s,x,t)=\sigma(s,x,t)\dot{W}(x,t)$

My problem is now, that I don't understand how this second order differential was constructed.
What are $(\kappa\Delta-\alpha)u$, $f(u,x,t)$, $\dot{M}(u,x,t)$ supposed to be here and what has this to do with waves?

If you can pinpoint me to some resources, which will make my life easier in understanding this. I will be very thankful!

2. Originally Posted by NoClue
Hello!

I am required to do a paper on the Semilinear Wave Equation as part of a Stochastic Partial Differential Equations seminar.
The problem is, that I've never taken a course on partial differential equations (only ordinary differential equations) or functional analysis.

Now I have the following in front of me:

Let $f(s,x,t)$ and $\sigma(s,x,t)$ be predictable random fields
depending on the parameters $s\in\mathbf{R}$ and $x\in D$. We consider
the initial-boundary value problems for a stochastic wave equation
as follows

$\frac{\partial^{2}u}{\partial t^{2}}=(\kappa\Delta-\alpha)u+f(u,x,t)+\dot{M}(u,x,t)$
$x\in D$, $t\in(0,T]$

$Bu$| $_{\partial D}=0$

$u(x,0)=g(x),$ $\frac{\partial u}{\partial t}(x,0)=h(x)$

where

$\dot{M}(s,x,t)=\sigma(s,x,t)\dot{W}(x,t)$

My problem is now, that I don't understand how this second order differential was constructed.
What are $(\kappa\Delta-\alpha)u$, $f(u,x,t)$, $\dot{M}(u,x,t)$ supposed to be here and what has this to do with waves?