Continuous functions on metric space, M

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Discussion Overview

The discussion revolves around the concept of continuous functions on a metric space, specifically focusing on the implications of such functions being bounded. Participants explore the definitions and contexts of these functions, as well as the characteristics of the metric space M.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • One participant questions the nature of the continuous function, asking whether it is a mapping from M to M or another type of mapping, and seeks clarification on the image of the function.
  • Another participant requests the original source of the statement regarding bounded continuous functions to provide context.
  • A third participant defines a bounded map from a set X to a metric space M, stating that the image f(X) is bounded if there exists a point x in X and an ε>0 such that f(X) is contained within a ball centered at f(x) with radius ε.
  • A later reply suggests that if f(p) = p is continuous, it implies that the metric space M itself is bounded.

Areas of Agreement / Disagreement

Participants express uncertainty about the definitions and implications of bounded continuous functions, and there is no consensus on the context or specific characteristics of the function in question.

Contextual Notes

Limitations include the lack of clarity on the specific context in which the statement about bounded continuous functions was made, as well as the need for further specification regarding the nature of the mapping and the metric space M.

roman93
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If every continuous function on M is bounded, what does this mean?

I am not sure what this function actually is... is it a mapping from M -> M or some other mapping? Is the image of the function in M? Any help would be greatly appreciated!
 
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roman93 said:
is it a mapping from M -> M or some other mapping?

I suggest that you explain where you saw this statement and quote it exactly.
 
A map f:X\rightarrow M where X is a set and M is a metric space, is called bounded if the image f(X) is bounded. This means that there is an x\in X and an \varepsilon>0 such that f(X)\subseteq B(f(x),\varepsilon).

This is what I would call bounded. But you will need to specify the context.
 
Since f(p)= p is continuous, one thing that tells you is that M itself is bounded!
 

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