The collection of all relations on a set.
111324
Finding number of relations on a set with 3 elements
72391
linear dependence proof using subsets
133762
A set which satisfies all conditions for a Group except associativity
16553
Cardinality of the set of all total orders on $\Bbb{N}$
145781
Is the collection of all functions between two sets a set?
125174
Combinatorial intuition of identity
158671
Cardinality of a set that consists of all existing cardinalities
122271
A subset of a transitive set is transitive
84780
Cartesian products as sets of all functions.
23225
Union of connected subsets is connected if intersection is nonempty
44623
Closed set as a countable intersection of open sets
25769
Finding all posets on a set
45949
Is there a simpler way of drawing relation maps?
98518
Cardinality of equivalence relations on N
65308
Axiom of Choice: Family of non-empty sets mutually disjoint or not?
111954
Computing the cardinality of a combinatorial set
21202
Axiom of choice is equivalent to every relation includes a function with the same domain