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
Owner confidence rating: High Entry average rating: No information on entry rating
[parent] meromorphic functions of several variables (Definition)
Definition 1   Let $\Omega \subset {\mathbb{C}}^n$ be a domain and let $h \colon \Omega \to {\mathbb{C}}$ be a function. $h$ is called meromorphic if for each $p \in \Omega$ there exists a neighbourhood $U \subset \Omega$ ($p \in U$ and two holomorphic functions $f, g$ defined in $U$ where $g$ is not identically zero, such that $h = f/g$ outside the set where $g = 0$

Note that $h$ is really defined only outside of a complex analytic subvariety. Unlike in one variable, we cannot simply define $h$ to be equal to $\infty$ at the poles and expect $h$ to be a continuous mapping to some larger space (the Riemann sphere in the case of one variable). The simplest counterexample in ${\mathbb{C}}^2$ is $(z,w) \mapsto z/w$ which does not have a unique limit at the origin. The set of points where there is no unique limit, is called the indeterminancy set. That is, the set of points where if $h = f/g$ and $f$ and $g$ have no common factors, then the indeterminancy set of $h$ is the set where $f = g = 0$

Bibliography

1
Lars Hörmander. An Introduction to Complex Analysis in Several Variables, North-Holland Publishing Company, New York, New York, 1973.
2
Steven G. Krantz. Function Theory of Several Complex Variables, AMS Chelsea Publishing, Providence, Rhode Island, 1992.




"meromorphic functions of several variables" is owned by jirka.
(view preamble | get metadata)

View style:

Also defines:  indeterminancy set

This object's parent.

Attachments:
meromorphic function on projective space must be rational (Theorem) by jirka
Log in to rate this entry.
(view current ratings)

Cross-references: factors, points, origin, limit, counterexample, Riemann sphere, continuous mapping, poles, variable, complex analytic subvariety, neighbourhood, function, domain

This is version 1 of meromorphic functions of several variables, born on 2006-06-19.
Object id is 8058, canonical name is MeromorphicFunctionsOfSeveralVariables.
Accessed 1621 times total.

Classification:
AMS MSC32A20 (Several complex variables and analytic spaces :: Holomorphic functions of several complex variables :: Meromorphic functions)

Pending Errata and Addenda
None.
Discussion
Style: Expand: Order:
forum policy

No messages.

Interact
post | correct | update request | add derivation | add example | add (any)