What is a Measure with Finite Mass?

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Discussion Overview

The discussion revolves around the concept of a measure with finite mass, exploring its definition and implications within the context of measure theory and functional analysis. Participants inquire about its relation to sigma-finiteness and its relevance in geometric measure theory.

Discussion Character

  • Exploratory, Technical explanation, Conceptual clarification

Main Points Raised

  • Kevin asks for clarification on what it means for a measure to have finite mass, questioning if it relates to sigma-finiteness.
  • One participant suggests that without context, it is difficult to define finite mass but implies it likely means the measure of the set is finite.
  • Another participant introduces the concept of m-currents and questions whether the inquiry pertains to geometric measure theory.
  • A later reply references a specific theorem from Peter Lax's functional analysis text, indicating that a signed measure m of finite total mass is defined over all Borel sets.
  • One participant clarifies that for a measure m to have finite mass, it must satisfy the condition |m|(Q) < infinity, where |m| represents the total variation of the measure.

Areas of Agreement / Disagreement

The discussion does not reach a consensus on the broader implications of finite mass, but participants generally agree on the basic definition related to total variation.

Contextual Notes

Participants do not fully explore the implications of sigma-finiteness or the specific applications of finite mass in different contexts, leaving some assumptions and definitions unaddressed.

homology
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Quick question: what does it mean for a measure to have finite mass? (is this another way of saying sigma finite or something?)

Thanks,

Kevin
 
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Without context it is hard to say. However, it probably means that the measure of the set in question is finite.
 
I wonder if you've come across linear operators called m-currents recently? Is this a question from geometric measure theory?
 
Lonewolf said:
I wonder if you've come across linear operators called m-currents recently? Is this a question from geometric measure theory?

Not recently, I'm aware of currents and they're on my short list (as is GMT). However, the question over what "they" mean by a measure with finite mass has popped up in a couple places. But here's one:

I'm using Peter Lax's functional analysis text (very nice by the way) and amoung many uses here's one:

Th. 14: Let Q be a compact hausdorff space, C(Q) the space of continuous real-valued functions on Q, normed by the max norm.

(i) C' consists of all signed measures m of finite total mass, defined over all Borel sets. That is, every bounded linear functional L on C(q) can be written as

L(f)=Integral over Q of f dm
and so on and so forth...
 
Ok then. What it means is that the measure m has to satisfy |m|(Q) < infinity, where |m| is the total variation of the measure m. That help you any?
 
Yeah that helps, thanks.

kevin
 

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