In rule method the null set is represented by
$\{\}$
$\phi $
$\{ x:x = x\} $
$\{ x:x \ne x\} $
State whether each of the following set is finite or infinite :
The set of animals living on the earth
How many elements has $P(A),$ if $A=\varnothing ?$
Which of the following are sets ? Justify your answer.
The collection of all even integers.
Which of the following sets are finite or infinite.
The set of prime numbers less than $99$
Make correct statements by filling in the symbols $\subset$ or $ \not\subset $ in the blank spaces:
$\{ 2,3,4\} \ldots \{ 1,2,3,4,5\} $