Intereting Posts

Infinite product of fields
Introductory texts on manifolds
Use the definition of the derivative to find $f'(x)$ for $f(x)=\sqrt{x-2}$
Show $2(x+y+z)-xyz\leq 10$ if $x^2+y^2+z^2=9$
What does it mean when two groups commute?
Recurrence substitution method
wanted: a lucid demonstration that these $m+n$ bilinear equations have a solution
Am I wrong in thinking that $e^{i \pi} = -1$ is hardly remarkable?
Need help with first order logic
Is the notation for '$a$ divides $b$' standard?
Meaning of pullback
Gamma Infinite Summation $\sum_{n=0}^{\infty}\frac{\Gamma(n+s)}{n!}=0$
How to prove $D^n/S^{n-1}\cong S^n$?
Positive integers less than 1000 without repeated digits
axioms of equality

We know that, indiscrete topology is the smallest topology. It has $2$ elements (they are the empty set and whole set). Suppose the given set is the empty set, then how can I define a topology on that set? Is it possible?

- Spaces where all compact subsets are closed
- Do we need net refinements not induced by preorder morphisms?
- Normal space- equivalent condition: $\forall U, V$ - open $: U \cup V = X \ \ \ \exists F \subset U \ , G \subset V$ - closed $: F \cup G = X$
- A question on star countable space
- Real Projective Space, $\mathbb P^n$, is Hausdorff.
- Equivalent metrics using open balls

- Why is $L^1(\mathbb{R}^n) \cap L^2(\mathbb{R}^n)$ dense in $ L^2(\mathbb{R}^n)$?
- Does the Jordan curve theorem apply to non-closed curves?
- Question about the proof that the Hilbert Cube is compact.
- Reconciling two different definitions of constructible sets
- Is it true that a subset that is closed in a closed subspace of a topological space is closed in the whole space?
- If the closure operator interchanges with tacking finite intersections, is this then true for a countable intersection?
- A generalization of the connected sum of links
- Prove: Every compact metric space is separable

If the underlying $X$ of a topological space is even allowed to be empty under our system of definitions, then $\{ \emptyset \}$ is the only such topology. Note that this is the same as the indiscrete topology $\{ \emptyset,X \}$ since $X=\emptyset$. It is also the same as the discrete topology $\mathcal{P}(X)$.

- Integral help here please?
- What is the intuition behind the unit normal vector being the derivative of the unit tangent vector?
- On the centres of the dihedral groups
- Examples of useful Category theory results?
- Unprovable things
- Isometric to Dual implies Hilbertable?
- Are localized rings always flat as R-modules?
- adjunction relation
- Does existence of anti-derivative imply integrability?
- Related to the partition of $n$ where $p(n,2)$ denotes the number of partitions $\geq 2$
- Showing that no Hamilton Circuit exists
- if matrix such $AA^T=A^2$ then $A$ is symmetric?
- How to show pre-compactness in Holder space?
- How to solve $f(x)+f\left(\frac{1}{x}\right)=e^{x+\frac{1}{x}}$
- Measure theory, measurable function, constant almost everywhere