New posts in separation-axioms

Examples for subspace of a normal space which is not normal

general-topology examples-counterexamples separation-axioms

How big can a separable Hausdorff space be?

general-topology separation-axioms separable-spaces

Do Hausdorff spaces that aren't completely regular appear in practice?

general-topology separation-axioms

Prove that a separable metric space is Lindelöf without proving it is second-countable

general-topology metric-spaces separation-axioms

The product of Hausdorff spaces is Hausdorff

general-topology separation-axioms product-space

Construction of a Hausdorff space from a topological space

general-topology category-theory separation-axioms

Quotient Space of Hausdorff space

general-topology riemann-surfaces quotient-spaces separation-axioms

Image of a normal space under a closed and continuous map is normal

general-topology separation-axioms closed-map

Every infinite Hausdorff space has an infinite discrete subspace

general-topology separation-axioms

How to show that topological groups are automatically Hausdorff?

general-topology topological-groups separation-axioms

Is the closure of a Hausdorff space, Hausdorff?

general-topology examples-counterexamples separation-axioms

Mrówka spaces are first-countable

general-topology compactness separation-axioms first-countable

A continuous bijection from a compact space to a $T_2$ space is always a homeomorphism

general-topology continuity compactness separation-axioms

When is $C_0(X)$ separable?

general-topology functional-analysis separation-axioms second-countable separable-spaces

Is there a simple method to prove that the square of the Sorgenfrey line is not normal?

general-topology separation-axioms product-space sorgenfrey-line

How many compact Hausdorff spaces are there of a given cardinality?

general-topology set-theory compactness cardinals separation-axioms

Question about quotient of a compact Hausdorff space

general-topology compactness quotient-spaces separation-axioms

If every continuous $f:X\to X$ has $\text{Fix}(f)\subseteq X$ closed, must $X$ be Hausdorff?

general-topology examples-counterexamples separation-axioms

Does $T_3$ imply that the topological space is zero-dimensional?

general-topology separation-axioms

Topology, Hausdorff and Fréchet space

general-topology separation-axioms