Is every relation which is transitive and symmetric also reflexive?
31392
Examples and Counterexamples of Relations which Satisfy Certain Properties
97801
If $R_{1}$ and $R_{2}$ are relations on a set S with $R_{1};R_{2}=R_{2};R_{1}$. Then $R_{1}$ and $R_{2}$ are bijective maps
111720
Is "have the same cardinality" a equivalence relation?
40937
Is the set of partial order relations over $ \mathbb{N}$ countable?
128060
Proof that the relation $5 \mid (a + 4b)$ is symmetric and transitive
140335
Prove that the empty relation is Transitive, Symmetric but not Reflexive
65910
Reflexivity of equivalence relations
18817
Does commutativity imply Associativity?
84819
Is statistical dependence transitive?
53101
Is it true that the relation |A| < |B| is a sufficient condition for claiming that $f$ is a bijection?
137921
Reflexivity, Transitivity, Symmertry of the square of an relation
35362
Number of equivalence relations on a set
66563
Is $ (A∪B)×(C∩D)=(A∪C)×(B∪D)$ true for all sets A,B,C and D?
25155
Suppose $R$ and $S$ are transitive relations on $A$. Prove that if $S \circ R \subseteq R \circ S$ then $R \circ S$ is transitive.
35124
Can every non-simple group $G$ be written as a semidirect product?
85713
Showing Parallelism is an equivalence relation in $\Bbb R ^2$
4151
Every subspace of a vector space has a complement