Proof that an affine scheme is quasi compact
128334
Question regarding open covers in Zariski topology (distinguished opens of affine schemes are quasi-compact)
50611
Question about Stone-Čech compactification
107370
An open covering of $\mathbb{Q} \cap [0,1]$ that does not contain any finite subcovering
97810
bijective morphism of affine schemes
156727
A step in the proof of Characterization of $W^{1,\infty}$
154363
Prove that $\text{aff}(X) = \text{aff}(\text{closure}(X))$
124036
Open affine neighborhood of points
104097
An idempotent operator is compact if and only if it is of finite rank
22131
Prove if nonempty $K \subset\mathbb{R}$ is compact, then both sup $K$ and inf $K$ exist and are elements of $K$.
158498
$A\subset \mathbb{R}$ with more than one element and $A/ \{a\}$ is compact for a fixed $a\in A$
7081
isometry $f:X\to X$ is onto if $X$ is compact
15491
Prove that $f:\mathbb R^n\to\mathbb R$ is affine if and only if it is convex and concave
153210
Why is every Noetherian zero-dimensional scheme finite discrete?
33370
Show that the one point compactification of $\mathbb{Q}$ is not Hausdorff
16643
A slick proof that a field which is finitely generated as a ring is finite
99707
free module implies surjective map of affine schemes
80202
Why is $[0, 1] \cap \mathbb{Q}$ not compact in $\mathbb{Q}$?