Types of sets ( finite and infinite) / cardinality/ standard infinite sets

Types of sets( finite and infinite)

1) Finite and infinite sets. 

2) Cardinal number of a set or order of a set.

= Number of distinct elements in a set is known as a cardinal number of a set.

it is represented in 3 ways :

i) n(A) - read as no of elements of set A

ii) O(A) - order of set A

iii) |A|

example:- A = {1,2,3,x,y}

n(A) = 5

3) Standard Infinite sets

i) N - set of all natural numbers

ii) W - set of all whole numbers

iii) R - set of all real numbers

iv) R⁺ - set of all +ve real numbers

v) R⁻ - set of all -ve real numbers

vi) Q - set of all rational numbers

vii) I , z - set of all integers

viii) I+ve or z+ve - set of all +ve integers

ix) I-ve or z-ve - set of all -ve integers

x) R - Q => set of all irrational numbers