Let S = {1, 2, 3, 4}. How many equivalence relation are there and describe them?
122839
how many different equivalence relations
80209
If $X,Y$ are equivalence relations, so is $X \times Y$
153306
Number of sigma algebras for set with 4 elements
87265
If $(A-\lambda{I})$ is $\lambda$-equivalent to $(B-\lambda{I})$ then $A$ is similar to $B$
111324
Finding number of relations on a set with 3 elements
131155
$x\sim y\iff x^2\equiv y^2\pmod{\!6}$ is an equivalence relation.
104987
Equivalence Relation with dividing x and y integers
91178
chain of divisibility relation
81068
Finding the left and right cosets of H = {(1), (12), (34), (12) ○ (34)} in S4
140724
How to prove two equivalence classes are disjoint?
98518
Cardinality of equivalence relations on N
55840
Number of functions from n-element set to {1, 2, …, m}
109318
Equivalence relation $(a,b) R (c,d) \Leftrightarrow a + d = b + c$
31392
Examples and Counterexamples of Relations which Satisfy Certain Properties
81197
Why is $SO(3)\times SO(3)$ isomorphic to $SO(4)$?
158009
Why is it always the case that, given an equivalence relation R on a set X and a $x \in X$, that x is equivalent to itself?
154735
$so(4)=su(2)× su(2)$