Difference between revisions of "Analytic operator"
From Encyclopedia of Mathematics
(Importing text file) |
m (TeX encoding is done) |
||
| Line 1: | Line 1: | ||
| − | + | {{TEX|done}} | |
| − | + | ''at a point $x_0$'' | |
| − | + | An operator $A$, acting from one [[Banach_space|Banach space]] into another, that admits a representation of the form | |
| − | + | \begin{equation} | |
| − | where | + | A(x_0+h) - Ax_0 = \sum_{k=1}^{\infty}C_kh^k, |
| + | \end{equation} | ||
| + | where $C_k$ is a form of degree $k$ and the series converges uniformly in some ball $\|h\|<r$. An operator is called analytic in a domain $G$ if it is an analytic operator at all points of this domain. An analytic operator is infinitely differentiable. In the case of complex spaces, analyticity of an operator in a domain is a consequence of its differentiability (according to Gâteaux) at each point of this domain. Examples of analytic operators are Lyapunov's integro-power series, and the Hammerstein and Urysohn operators with smooth kernels on the space $\mathcal C$ of continuous functions. | ||
====References==== | ====References==== | ||
<table><TR><TD valign="top">[1]</TD> <TD valign="top"> E. Hille, R.S. Phillips, "Functional analysis and semi-groups" , Amer. Math. Soc. (1957)</TD></TR><TR><TD valign="top">[2]</TD> <TD valign="top"> M.A. Krasnosel'skii, G.M. Vainikko, P.P. Zabreiko, et al., "Approximate solution of operator equations" , Wolters-Noordhoff (1972) (Translated from Russian)</TD></TR></table> | <table><TR><TD valign="top">[1]</TD> <TD valign="top"> E. Hille, R.S. Phillips, "Functional analysis and semi-groups" , Amer. Math. Soc. (1957)</TD></TR><TR><TD valign="top">[2]</TD> <TD valign="top"> M.A. Krasnosel'skii, G.M. Vainikko, P.P. Zabreiko, et al., "Approximate solution of operator equations" , Wolters-Noordhoff (1972) (Translated from Russian)</TD></TR></table> | ||
Latest revision as of 06:35, 18 December 2012
at a point $x_0$
An operator $A$, acting from one Banach space into another, that admits a representation of the form \begin{equation} A(x_0+h) - Ax_0 = \sum_{k=1}^{\infty}C_kh^k, \end{equation} where $C_k$ is a form of degree $k$ and the series converges uniformly in some ball $\|h\|<r$. An operator is called analytic in a domain $G$ if it is an analytic operator at all points of this domain. An analytic operator is infinitely differentiable. In the case of complex spaces, analyticity of an operator in a domain is a consequence of its differentiability (according to Gâteaux) at each point of this domain. Examples of analytic operators are Lyapunov's integro-power series, and the Hammerstein and Urysohn operators with smooth kernels on the space $\mathcal C$ of continuous functions.
References
| [1] | E. Hille, R.S. Phillips, "Functional analysis and semi-groups" , Amer. Math. Soc. (1957) |
| [2] | M.A. Krasnosel'skii, G.M. Vainikko, P.P. Zabreiko, et al., "Approximate solution of operator equations" , Wolters-Noordhoff (1972) (Translated from Russian) |
How to Cite This Entry:
Analytic operator. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Analytic_operator&oldid=29225
Analytic operator. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Analytic_operator&oldid=29225
This article was adapted from an original article by P.P. Zabreiko (originator), which appeared in Encyclopedia of Mathematics - ISBN 1402006098. See original article