Learning Functional Programming in Go

Set theory symbols

Before moving forward with category theory, let's get familiar with the symbols of set theory:

Symbol	Symbol name	Meaning/definition	Example
{ }	Set	A collection of objects (also known as elements)	A = {5,6,7,8}, B = {5,8,10}
|	Such that	So that	A = {x | x ∈ ℝ, x<0}
A∩B	Intersection	Objects that belong to set A and set B	A ∩ B = {5,8}
A∪B	Union	Objects that belong to set A or set B	A ∪ B = {5,6,7,8,10}
A⊆B	Subset	A is a subset of B. Set A is included in set B	{5,8,10} ⊆ {5,8,10}
A⊂B	Proper subset / Strict subset	A is a subset of B, but A is not equal to B	{5,8} ⊂ { 5,8,10}
A⊄B	Not subset	Set A is not a subset of set B	{8,15} ⊄ {8,10,25}