State which of the following sets are finite or infinite :
$\{ x:x \in N$ and $x$ is prime $\} $
Let $A=\{1,2,\{3,4\}, 5\} .$ Which of the following statements are incorrect and why ?
$1 \subset A$
Write down all the subsets of the following sets
$\{ a\} $
State whether each of the following set is finite or infinite :
The set of lines which are parallel to the $x\,-$ axis
In each of the following, determine whether the statement is true or false. If it is true, prove it. If it is false, give an example.
If $x \in A$ and $A \in B,$ then $x \in B$