PlanetMath (more info)
 Math for the people, by the people. Sponsor PlanetMath
Encyclopedia | Requests | Forums | Docs | Wiki | Random | RSS  
Login
create new user
name:
pass:
forget your password?
Main Menu
Revision difference : plurisubharmonic function
Version current Version 5
\begin{defn} \begin{defn}
Let $f \colon G \subset {\mathbb{C}}^n \to {\mathbb{R}}$ be an upper semi-continuous function. $f$ is called {\em plurisubharmonic} Let $f \colon G \subset {\mathbb{C}}^n \to {\mathbb{R}}$ be an upper semi-continuous function. $f$ is called {\em plurisubharmonic}
if for every complex line $\{ a + b z \mid z \in {\mathbb{C}} \}$ if for every complex line $\{ a + b z \mid z \in {\mathbb{C}} \}$
the function $z \mapsto f(a + bz)$ is a subharmonic function on the set the function $z \mapsto f(a + bz)$ is a subharmonic function on the set
$\{ z \in {\mathbb{C}} \mid a + b z \in G \}$. $\{ z \in {\mathbb{C}} \mid a + b z \in G \}$.
\end{defn} \end{defn}
Similarly, we could also define a {\em plurisuperharmonic} function just like Similarly we could also definie a {\em plurisuperharmonic} function just like
we have a superharmonic function, but again it just means that $-f$ is we have a superharmonic function, but again it just means that $-f$ is
plurisubharmonic, and so this extra \PMlinkescapetext{term} is not very useful. plurisubharmonic and so this extra term is not very useful.
\begin{defn} \begin{defn}
A continuous plurisubharmonic function is said to be a {\em pseudoconvex function}. If $f$ is a plurisubharmonic function and further $f$ is continuous, then
$f$ is called a {\em pseudoconvex function}.
\end{defn} \end{defn}
Note that since plurisubharmonic is a long word, many authors abbreviate Note that since plurisubharmonic is a long word, many authors abbreviate
with {\em psh}, {\em plsh}, or {\em plush}. with {\em psh}, {\em plsh} or {\em plush}.
\begin{thebibliography}{9} \begin{thebibliography}{9}
\bibitem{Krantz:several} \bibitem{Krantz:several}
Steven~G.\@ Krantz. Steven~G.\@ Krantz.
{\em \PMlinkescapetext{Function Theory of Several Complex Variables}}, {\em \PMlinkescapetext{Function Theory of Several Complex Variables}},
AMS Chelsea Publishing, Providence, Rhode Island, 1992. AMS Chelsea Publishing, Providence, Rhode Island, 1992.
\end{thebibliography} \end{thebibliography}