Is the Quotient Space X/Y Hausdorff When X is Locally Compact?

  • Thread starter christianrhiley
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In summary: X is contained in Y, then it's not going to be separable from Y, right?)In summary, the problem is asking to show that a quotient space X/Y, where X is a locally compact Hausdorff space and Y is a subspace, is also a Hausdorff space. This means that distinct points in X/Y must have disjoint open neighborhoods, even after collapsing Y. This requires finding disjoint neighborhoods that also do not intersect Y for points not contained in Y.
  • #1
christianrhiley
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Problem:
Let X be a locally compact Hausdorff space, Y a subspace. Show that the quotient space X/Y is a Hausdorff space.

My attempt at a solution:
I don't have a solution. I cannot connect a Hausdorff space with a quotient space.

Since X is compact Hausdorff x,y [tex]\in[/tex] X s.t. x and y can be separated by neighborhoods if [tex]\exists[/tex] a neighborhood U of x and V of y s.t. U /\ V = [tex]\phi[/tex]. Now, somehow this implies that, for open sets U, the [tex]\bigcup[/tex] U [tex]\subset[/tex] X are disjoint.
 
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  • #2
Normally, a topological space is quotiented by an equivalence relation, not a subspace.
 
  • #3
if you are collapsing the subspace Y to a point, maybe you want a closed subspace?

then you would be asking whether any point not in that subspace can be separated from it by disjoint open neighborhoods.

it still seems kind of odd. i guess i need more definitions. what does locally compact mean?in a hausdorff space, distinct points have disjoint open neighborhoods, so you want them to still be disjoint after collapsing Y? so you need disjoint nbhds that also miss Y? (and that's for points not themselves contained in Y...
 
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What is a Hausdorff space?

A Hausdorff space is a type of topological space in which every pair of distinct points have disjoint neighborhoods. This means that for any two points in the space, there exists open sets around each point that do not overlap.

Why are Hausdorff spaces important?

Hausdorff spaces are important because they provide a higher level of separation between points compared to other topological spaces. This allows for more precise mathematical analysis and better understanding of the structure of the space.

What are some examples of Hausdorff spaces?

Examples of Hausdorff spaces include Euclidean spaces, metric spaces, and compact spaces. Other common examples include the real line, the complex plane, and finite topological spaces.

What is the relationship between Hausdorff spaces and continuity?

Hausdorff spaces are closely related to the concept of continuity in mathematics. In fact, a function between two topological spaces is continuous if and only if the preimage of any open set is open, and the space in question must be a Hausdorff space.

How are Hausdorff spaces used in real-world applications?

Hausdorff spaces have numerous applications in mathematics, physics, and engineering. They are used to study the properties of topological spaces, analyze complex systems, and develop algorithms for data analysis. They also have practical applications in computer vision, image processing, and machine learning.

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