Part 5
String Length

Since mathematical string is a set of elements following each other in a certain sequence, the length of the sequence can be measured. The length of the string is simply the number of characters in that string.  The length of an empty string is zero.

We use two vertical bars around the string to denote it’s length: |  | 

Example:

If we have string α = <x>, then it’s length is | α | = 1;

If we have string β = <☺> o <☼> o <♥> , then | β | = 3.