Complex function of several variables

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Homework Help Overview

The discussion revolves around the continuity of complex functions of several variables within the context of complex analysis, specifically focusing on definitions and properties related to metric spaces. The original poster seeks clarification on continuity definitions and metrics in complex Euclidean spaces.

Discussion Character

  • Conceptual clarification, Assumption checking, Mixed

Approaches and Questions Raised

  • The original poster attempts to define continuity for complex functions of several variables and questions the appropriate metric for points in complex Euclidean space. Participants discuss the general definition of continuity in metric spaces and the specific metric formula for distance between points.

Discussion Status

Some participants provide insights regarding the continuity definition in metric spaces and confirm the metric formula. There is also a request for book recommendations on complex functions of several variables, indicating a search for foundational concepts. The discussion touches on the Heine-Borel theorem and its applicability in complex Euclidean spaces, with some participants affirming its validity.

Contextual Notes

The original poster expresses difficulty finding resources that cover basic concepts such as continuity and limits in the context of complex functions of several variables. There is an indication of uncertainty regarding the Heine-Borel theorem's applicability in this setting.

gotjrgkr
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Hi!

While studying Global Cauchy Theorems in complex analysis, I've realized that I need to know a definition of continuity of a complex function of several variables...
Thus, I ask you the definition of continuity of a complex function of several complex variables.
What I mean is ... ; Given a complex valued function F of several complex variables(F:A\rightarrowC where A is a subset of C^{n} for a positive integer n and C implies the complex plane), What does it mean F is continuous at a point x in A for this function??

In addition, I also ask you whether the definition of metric of a point x=(z_{1},...,z_{n}) in the comples euclidean space C^{n} is just \sqrt{\sum^{n}_{i=1}\left|z_{i}\right|^{2}} or not??
 
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Yes, it's a metric space. So the definition of continuity is the same as in any metric space. But a metric is the distance between two points x=(z_1,...,z_n) and x'=(z'_1,...,z'_n) and that would be d(x,x')=\sqrt{\sum^{n}_{i=1}\left|z_{i}-z'_{i}\right|^{2}}.
 
Dick said:
Yes, it's a metric space. So the definition of continuity is the same as in any metric space. But a metric is the distance between two points x=(z_1,...,z_n) and x'=(z'_1,...,z'_n) and that would be d(x,x')=\sqrt{\sum^{n}_{i=1}\left|z_{i}-z'_{i}\right|^{2}}.

Oh,, I see...
I also wanted to get such an answer for my question.
1. But, I couldn't find any book dealing with a complex function of several variables.
Of course, there's a book dealing with such a kind of field. But, it seems that almost every book omit the basic part of it such as continuity, limit, and topology related with higer dimensional complex metric space... So, could you recommend a book explaining such basic parts of the complex function of several variables ( basic concepts such as continuity, definition of metric of the space, limit, etc).
I know this is a quite a different question for the main question, but
2. I also want to ask you if in the complex euclidean space(considered as a metric space as you show) Heine-Borel Theorem still holds or not(I mean that a subset is compact in the metric space iff the subset is closed and bounded in the metric space)...
 
gotjrgkr said:
2. I also want to ask you if in the complex euclidean space(considered as a metric space as you show) Heine-Borel Theorem still holds or not(I mean that a subset is compact in the metric space iff the subset is closed and bounded in the metric space)...

Yes. \mathbb{C} is isomorphic with \mathbb{R}^2 and the Heine-Borel theorem holds in \mathbb{R}^2.
 

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