Find the cardinality of this set: $\{x \subseteq \mathbb R : |x| < \aleph_o\}$
101669
Cardinality of the Set of all finite subset of $\mathbb{R}$
16553
Cardinality of the set of all total orders on $\Bbb{N}$
9651
Cardinality of cartesian product of an infinite set with N
158671
Cardinality of a set that consists of all existing cardinalities
20085
What's the cardinality of all sequences with coefficients in an infinite set?
17987
Which of the following sets has the greatest cardinality?(Math subject GRE exam 0568 Q.61 )
15733
Show that the cardinality of $\mathbb N$ is the same as the cardinality of $\mathbb N \times \mathbb N$
102972
Cardinality of $\mathbb{R}^\mathbb{R}$ by diagonal argument
153305
Adding subsets of regular cardinals (Jech p. 226)
68490
For $x\in\mathbb R\setminus\mathbb Q$, the set $\{nx-\lfloor nx\rfloor: n\in \mathbb{N}\}$ is dense on $[0,1)$
109968
Let $X= \{ A \subset \mathbb{N} : \mathbb{N} \backslash A \text{ is finite}\}$. What is the cardinality of $X$? Prove it.
82947
Undecidable cardinality
149382
Prove that $(0,1) \subseteq\mathbb R$ and $(4,10) \subseteq\mathbb R$ have the same cardinality.
10909
$|A \cup B| = \mathfrak{c}$, then $A$ or $B$ has cardinality $\mathfrak{c}$.
81509
The cardinality of a countable union of countable sets, without the axiom of choice
135698
Count subsets whose cardinalities are congruent to 0, 1 and 2 modulo 3 respectively
78422
Calculate the number $o(\mathbb{R})$ of open subsets of the real line.