Elements in a set that are not elements of another set (relative complement)
67216
Matlab arrays operation
107215
Is $\emptyset \in \emptyset$ or $\emptyset \subseteq \emptyset$?
26398
Group of even order contains an element of order 2
141318
$\subset$ vs $\subseteq$ when *not* referring to strict inclusion
106670
Existence of vector space complement and axiom of choice
79826
$gHg^{-1}\subset H$ whenever $Ha\not = Hb$ implies $aH\not =bH$
147941
comparing sup and inf of two sets
24685
Expressing a Countable Union of Sets as the Countable Union of Disjoint Sets (e.g. Eliminating Duplicate Intersections)
2287
If a set is linearly independent, a finite subset of that set is also linearly independent
47056
Show that the boundary of a set equals the boundary of its complement
66225
Word for two collections that do not have any elements in common
64519
Subsets of a list
111032
Proof of Sets involving the Cartesian Product
125077
what is the absolute value of a set?
144181
Given an arbitrary set $X$, can one always find an element outside $X$?
2935
Completness and Set of Result of One Set ?!?
3896
A closed set in $(A, \mathcal T_A)$ that is not closed in $(X, \mathcal T)$