<?xml version="1.0" encoding="UTF-8"?>

<record version="7" id="2815">
 <title>integral transform</title>
 <name>IntegralTransform</name>
 <created>2002-04-05 17:14:52</created>
 <modified>2008-09-03 18:59:40</modified>
 <type>Definition</type>
 <creator id="13766" name="PrimeFan"/>
 <author id="13766" name="PrimeFan"/>
 <author id="2760" name="yark"/>
 <author id="4370" name="mathforever"/>
 <author id="22" name="vampyr"/>
 <classification>
	<category scheme="msc" code="65R10"/>
 </classification>
 <defines>
	<concept>kernel</concept>
	<concept>transform parameter</concept>
 </defines>
 <related>
	<object name="ContourIntegral"/>
	<object name="GroupHomomorphism"/>
 </related>
 <preamble>\usepackage{amssymb}
\usepackage{amsmath}
\usepackage{amsfonts}
</preamble>
 <content>\PMlinkescapeword{generic}
\PMlinkescapeword{transform}

A generic \emph{integral transform} takes the form $$F(p)  =  \int_\alpha^\beta K(p, t) f(t)dt,$$ with $p$ being the {\em transform parameter}.

Note that the transform takes a function $f(t)$ and produces a new function $F(p)$.

The function $K(p, t)$ is called the \emph{kernel} of the transform.  The kernel of an integral transform, along with the \PMlinkname{limits}{DefiniteIntegral} $\alpha$ and $\beta$, distinguish a particular integral transform from another.  

\subsection*{Examples}
\begin{itemize}
\item Laplace transform
\begin{gather*}
\alpha = 0,\; \beta = \infty,\; K(p,t) = e^{-pt},\\
F(p) = \int\limits_0^\infty e^{-pt} f(t) dt.
\end{gather*}

\item Laplace-Carson transform
\begin{gather*}
\alpha = 0,\; \beta = \infty,\; K(p,t) = pe^{-pt},\\
F(p) = \int\limits_0^\infty pe^{-pt} f(t) dt.
\end{gather*}

\item Fourier transform
\begin{gather*}
\alpha = -\infty,\; \beta = \infty,\; K(p,t) = \frac{1}{\sqrt{2\pi}}e^{-ipt},\\
F(p) = \frac{1}{\sqrt{2\pi}}
	\int\limits_{-\infty}^\infty e^{-ipt} f(t) dt.
\end{gather*}
\end{itemize}</content>
</record>
