Namespaces
Variants
Actions

Difference between revisions of "Nekrasov integral equation"

From Encyclopedia of Mathematics
Jump to: navigation, search
(Importing text file)
 
(TeX)
Line 1: Line 1:
 +
{{TEX|done}}
 
A non-linear integral equation of the form
 
A non-linear integral equation of the form
  
<table class="eq" style="width:100%;"> <tr><td valign="top" style="width:94%;text-align:center;"><img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n066/n066280/n0662801.png" /></td> <td valign="top" style="width:5%;text-align:right;">(*)</td></tr></table>
+
$$\phi(x)=\lambda\int\limits_a^b[\phi(y)+R(\lambda,y,\phi(y))]K(x,y)dy,\tag{*}$$
  
where <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n066/n066280/n0662802.png" /> and <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n066/n066280/n0662803.png" /> are known functions, <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n066/n066280/n0662804.png" /> being symmetric, <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n066/n066280/n0662805.png" /> is the unknown function, and <img align="absmiddle" border="0" src="https://www.encyclopediaofmath.org/legacyimages/n/n066/n066280/n0662806.png" /> is a numerical parameter. Integral equations of this type were obtained by A.I. Nekrasov (see [[#References|[1]]]) in the solution of problems arising in the theory of waves on the surface of a fluid. Under certain conditions Nekrasov has constructed a solution of (*) in the form of a series in powers of a small parameter; its convergence has been proved by the method of majorants.
+
where $R$ and $K$ are known functions, $K$ being symmetric, $\phi$ is the unknown function, and $\lambda$ is a numerical parameter. Integral equations of this type were obtained by A.I. Nekrasov (see [[#References|[1]]]) in the solution of problems arising in the theory of waves on the surface of a fluid. Under certain conditions Nekrasov has constructed a solution of \ref{*} in the form of a series in powers of a small parameter; its convergence has been proved by the method of majorants.
  
Sometimes an equation of the type (*) is called a [[Hammerstein equation|Hammerstein equation]], although Nekrasov [[#References|[2]]] published his investigations before A. Hammerstein [[#References|[3]]].
+
Sometimes an equation of the type \ref{*} is called a [[Hammerstein equation|Hammerstein equation]], although Nekrasov [[#References|[2]]] published his investigations before A. Hammerstein [[#References|[3]]].
  
 
====References====
 
====References====

Revision as of 10:04, 20 September 2014

A non-linear integral equation of the form

$$\phi(x)=\lambda\int\limits_a^b[\phi(y)+R(\lambda,y,\phi(y))]K(x,y)dy,\tag{*}$$

where $R$ and $K$ are known functions, $K$ being symmetric, $\phi$ is the unknown function, and $\lambda$ is a numerical parameter. Integral equations of this type were obtained by A.I. Nekrasov (see [1]) in the solution of problems arising in the theory of waves on the surface of a fluid. Under certain conditions Nekrasov has constructed a solution of \ref{*} in the form of a series in powers of a small parameter; its convergence has been proved by the method of majorants.

Sometimes an equation of the type \ref{*} is called a Hammerstein equation, although Nekrasov [2] published his investigations before A. Hammerstein [3].

References

[1] A.I. Nekrasov, "Collected works" , 1 , Moscow (1961) (In Russian)
[2] A.I. Nekrasov, Izv. Ivanovo-Vozn. Politekhn. Inst. , 6 (1922) pp. 155–171
[3] A. Hammerstein, "Nichtlineare Integralgleichungen nebst Anwendungen" Acta Math. , 54 (1930) pp. 117–176


Comments

References

[a1] P.P. Zabreiko (ed.) A.I. Koshelev (ed.) M.A. Krasnoselskii (ed.) S.G. Mikhlin (ed.) L.S. Rakovshchik (ed.) V.Ya. Stet'senko (ed.) T.O. Shaposhnikova (ed.) R.S. Anderssen (ed.) , Integral equations - a reference text , Noordhoff (1975) (Translated from Russian)
How to Cite This Entry:
Nekrasov integral equation. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Nekrasov_integral_equation&oldid=33346
This article was adapted from an original article by B.V. Khvedelidze (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article