Definition of semialgebra of sets
102223
Question about definition of Semi algebra
155063
Is Cl(f(A)) a subset of f(Cl(A))?
122506
Relation on countable sets
92390
The meaning of notation $\subset\subset$ in complex analysis
82487
Define a mathematical set
51434
What does the symbol $\subset\subset$ mean?
71976
Is every element on a set also a set?
44160
Set theory: difference between belong/contained and includes/subset?
118239
If $A, B, C$ are sets prove that $(A\setminus B)\setminus C\subseteq A\setminus(B\setminus C)$
39226
What's the meaning of a set to the power of another set?
107383
Derived sets - prove $(A \cup B)' = A' \cup B'$
13779
Canonical copies of sets
31710
Show that $\mathcal{J}=\{[a, a+1) \mid a \in \mathbb{R}\}$ generates the Borel set of $\mathbb{R}$
104308
Proving a set is a Sigma Algebra
125077
what is the absolute value of a set?
95373
Additive set function on a semiring of sets
858
Is $\{\emptyset\}$ a subset of $\{\{\emptyset\}\}$?