Amount of transitive relations on a finite set
57954
How many transitive relations on a set of $n$ elements?
67451
Building a bijection from a finite union of countable sets to $\mathbb{N}$
146098
Number of nonempty subsets of a set with $n$ elements
62687
Proving Cardinality of Cosets in Abstract Algebra
3465
Equivalence relations and power sets.
117479
Mutual set of representatives for left and right cosets: what about infinite groups?
122271
A subset of a transitive set is transitive
138436
How to prove reflexivity, symmetry and transitivity for the following relation?
103769
The Cartesian product of a finite number of countable sets is countable
40937
Is the set of partial order relations over $ \mathbb{N}$ countable?
127233
Cardinality of order types in $\mathbb{N}$
104112
Number of finite simple groups of given order is at most $2$ - is a classification-free proof possible?
74114
How to find the number of anti-symmetric relations?
149673
Cardinality of an infinite union of finite sets
3217
Construction of uncountably many non-isomorphic linear (total) orderings of natural numbers
64118
Number of elements in a finite $\sigma$-algebra
68230
The cardinality of a countable union of sets with less than continuum cardinality