Dense set in cofinite topology
97064
Dense set in an infinite cofinite space
102250
Subset of $C[0,1]$ is nowhere dense
88595
Prob. 21, Sec. 17 in Munkres' TOPOLOGY, 2nd ed: Closure and complementation can result in at most 14 different sets
85870
Show this set is a base for some topology on $\mathbb{Z}$
103717
Topological Property of the Set of Integers
66334
How is every subset of the set of reals with the finite complement topology compact?
14048
Proof that the complement of zero-measure set on $[0,1]$ is dense in $[0,1]$
144362
The construction of a Vitali set
44430
Is there an open dense set $S \subset [0,1]$ such that $m(S)<1$?
116542
Which of the following sets are compact in $\mathbb{M}_n(\mathbb{R})$[NBHM_PhD Screening Test-2013, Topology]
137621
The Number of Topologies on a Finite Set
66239
Verifying that a certain collection of intervals of $\mathbb R$ forms a topology
68230
The cardinality of a countable union of sets with less than continuum cardinality
136108
Arbitrary intersection of closed, connected subsets of a compact space connected?
53429
In a complete metric space with no isolated points, any countable intersection of open dense sets is uncountable?
115625
Intersection of two open dense sets is dense
158011
$C_c^{\infty}(\mathbb R^n)$ is dense in $W^{k,p}(\mathbb R^n)$