Variables
- A particular element in a set is referenced by the name of the element, e.g., the element 55 in Naturals
- A general or generic element is referenced by a variable name or variable,
e.g.
n ∈ Naturals, name ∈ Students, city ∈ USCities, x ∈ Naturals
we say: n is a variable over Naturals or the range of n is Naturals
- A variable can be assigned any value in its range, e.g.