What is a Measure with Finite Mass?

In summary, a measure having finite mass means that the measure of the set in question is finite. This could also be referred to as being sigma finite. In a specific example from a functional analysis text, it means that the measure must satisfy |m|(Q) < infinity, where |m| is the total variation of the measure m.
  • #1
homology
306
1
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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  • #2
Without context it is hard to say. However, it probably means that the measure of the set in question is finite.
 
  • #3
I wonder if you've come across linear operators called m-currents recently? Is this a question from geometric measure theory?
 
  • #4
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...
 
  • #5
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?
 
  • #6
Yeah that helps, thanks.

kevin
 

What is a measure with finite mass?

A measure with finite mass is a mathematical concept used in the field of measure theory. It refers to a type of measure that assigns a finite value to sets within a given space. This measure is often used to quantify the size or extent of a set or collection of objects.

How is a measure with finite mass different from other types of measures?

A measure with finite mass differs from other types of measures, such as countable measures or infinite measures, in that it assigns a finite value to sets instead of an infinite or countable value. This makes it useful for measuring finite quantities or objects.

What are some examples of measures with finite mass?

Examples of measures with finite mass include the Lebesgue measure, which is used to measure the size of sets in Euclidean space, and the counting measure, which assigns a value of 1 to each element in a set. Other examples include the length, area, and volume measures used in geometry and calculus.

How are measures with finite mass used in real-world applications?

Measures with finite mass have a wide range of applications in various fields, such as physics, economics, and statistics. They can be used to measure quantities, probabilities, and distributions, and are often used in modeling and analysis of real-world phenomena.

What are some key properties of measures with finite mass?

Some key properties of measures with finite mass include additivity, which means that the measure of a union of disjoint sets is equal to the sum of their individual measures, and monotonicity, which means that the measure of a larger set is greater than the measure of a smaller set. Measures with finite mass also satisfy countable subadditivity and translation invariance properties.

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