1.3.2 Common Sets

Some commonly used sets are:

•  denotes the set of natural numbers; i.e. {1, 2, 3, …}
•  denotes the set of integers; i.e. {…, −2, −1, 0, 1, 2, …}
•  denotes the set of rational numbers i.e. a set of all possible fractions, including the integers; i.e. {integer ratios /,   }
•  denotes the set of real numbers i.e. a set of rational numbers and irrational numbers { ∣  is an element of the set of rational numbers or  is an element of the set of irrational numbers}