Sets
Collection of elements
- Enumeration of elements
{1,{1,4,7}, 4}, {red, yellow}, {} (also written as ?)
- Defining Property
{x | P(x)}
{x | x is an even integer}
Examples:
Natural numbers N = {0,1,2,3,4,5,…}
Integers Z = { …-2,-1, 0, 1, 2, …}
Truth Values (Booleans) B = {True, False}
Rational Numbers Q = {x|x = p/q for some p,q ?Z, q ?0}