Number of onto functions from set A to B
61
Calculating the total number of surjective functions
90566
There exists surjections from A onto B and vice versa, and there is no bijection between the sets?
46971
Number of surjections from $\{1,...,m\}$ to $\{1,...,n\}$
82207
Number of Pairs of Subsets
78422
Calculate the number $o(\mathbb{R})$ of open subsets of the real line.
40486
Number of One-to-One Functions
111954
Computing the cardinality of a combinatorial set
97878
Are there uncountably many surjections from $\mathbb N$ to $\mathbb N$?
14711
set theoretic function, products of sets (product versus Cartesian product)
42794
Prove that functions map countable sets to countable sets
62709
Functions that are sets of all function - proofs
57954
How many transitive relations on a set of $n$ elements?
79974
The cardinality of Lebesgue sets
5375
Is there a bijective function mapping Natural numbers to Natural numbers, other than $f(n) = n$?
137621
The Number of Topologies on a Finite Set
119084
How many ordered pairs $(A,B)$ they are if $A$ and $B$ are subsets of $\{ 1,2,3,4,5 \}$ such that $A \cap B = \{1\}$?
128766
Show that the set of functions $\mathbb{N}\to\{0,1\}$ is not countable