
What is a discrete set exactly? - Mathematics Stack Exchange
Oct 6, 2016 · 5 A topology has nothing to do with the set or the elements. Any set whether it is the set {1,2,3} {1, 2, 3} which is finite, or the set of real functions which is a higher uncountability …
Why discrete set must be countable? - Mathematics Stack Exchange
Any discrete subset S of Euclidean space must be countable, since the isolation of each of its points together with the fact that rationals are dense in the reals means that the points of S …
Discrete subsets in real analysis - Mathematics Stack Exchange
Mar 8, 2014 · A discrete set defined hereby is essentially a formalisation of the general notion of discreteness we have used so soften. The set $\ {1, 2, 3, ..\}$ is discrete in the sense that …
elementary set theory - Are finite sets discrete by definition ...
Are finite sets countable by definition? I was first wondering about whether a discrete set was countable by definition, but this page states that a discrete set has to be either finite or countabl...
Example of discrete set - Mathematics Stack Exchange
Feb 3, 2016 · For example. The Rational numbers aren't discrete because every interval around a rational will contain and infinite number of other rationals. The reals aren't discrete either. The …
What does "discrete" really mean, in plain English?
Aug 21, 2020 · A discrete set in a metric space or other topological space, such as the line or the plane or $3$ -dimensional Euclidean space, is a space in which every points is (topologically) …
general topology - Intersection of compact and discrete subsets ...
A discrete set according to Arthur's definition is automatically closed (as a point in the closure but not in the set would violate discreteness). So most likely, if you are supposed to show that the …
Is a discrete set inside a compact space necessarily finite?
May 31, 2015 · 8 Abramodj: I just want to point out that closed discrete subset of a compact space is finite is consequence of a more general fact that a discrete space is compact iff it is finite. …
Does proper map $f$ take discrete sets to discrete sets?
May 24, 2015 · I think that the correct statement is that a proper function maps closed discrete sets to closed discrete subsets. In this case D is not closed and its closure is not discrete.
general topology - example of a discrete set which is closed ...
Sep 3, 2017 · example of a discrete set which is closed Ask Question Asked 8 years, 3 months ago Modified 8 years, 3 months ago