Which of the following are sets ? Justify your answer.
A team of eleven best-cricket batsmen of the world.
Which of the following are sets ? Justify your answer.
The collection of questions in this chapter.
Write down all the subsets of the following sets
$\{ a\} $
State which of the following sets are finite or infinite :
$\{ x:x \in N$ and ${x^2} = 4\} $
Examine whether the following statements are true or false :
$\{ a\} \in \{ a,b,c\} $