The relation "is subset of" on the power set $P(A)$ of a set $A$ is

Let $R _{1}=\{( a , b ) \in N \times N :| a - b | \leq 13\}$ and $R _{2}=\{( a , b ) \in N \times N :| a - b | \neq 13\} .$ Thenon $N$

If $\mathrm{R}$ is the smallest equivalence relation on the set $\{1,2,3,4\}$ such that $\{(1,2),(1,3)\} \subset R$, then the number of elements in $\mathrm{R}$ is

Let $A=\{1,2,3\} .$ Then number of relations containing $(1,2)$ and $(1,3)$ which are reflexive and symmetric but not transitive is

Let $R$ be a relation on $R$, given by $R=\{(a, b): 3 a-3 b+\sqrt{7}$ is an irrational number $\}$. Then $R$ is

Let $R$ and $S$ be two equivalence relations on a set $A$. Then