Sets Basics

Membership

A set is made up of elements.

e.g.

$A = {d o g, c a t, h a m s t e r}$

$d o g \in A$

$e l e p h a n t \notin A$

The cardinality of a set is the number of elements

e.g. $| A | = 3$

The elements that are in both sets

e.g.

$A = {d o g, c a t, h a m s t e r}$

$B = {d o g, h e l i c o p t e r, d i n o s a u r}$

$A \cap B = {d o g}$

All the elements that are in either set
e.g.

$A = {d o g, c a t, h a m s t e r}$

$B = {d o g, h e l i c o p t e r, d i n o s a u r}$

$A \cup B = {d o g, c a t, h a m s t e r, h e l i c o p t e r, d i n o s a u r}$

| A \cup B | = | A | + | B | - | A \cap B |

Based on course material by Paul Bendich and Daniel Egger from Data Science Maths Skills