Answer
We will use the fact that every rational number is of the form $\frac{a}{b}$ where $A$ and $B$ are integers
Take the list of characters to be {${0,1,2,3,4,5,6,7,8,9,/,-}$} every integer in the standard numeral system.
Then every rational number is labeled with a finite string of characters from our list of characters the character(Put the $/$ to distinguish the two integers and the character if the number is negative).
Then we have satisfied the condition of exercise 25. Hence we have a result.
Work Step by Step
We will use the fact that every rational number is of the form $\frac{a}{b}$ where $A$ and $B$ are integers
Take the list of characters to be {${0,1,2,3,4,5,6,7,8,9,/,-}$} every integer in the standard numeral system.
Then every rational number is labeled with a finite string of characters from our list of characters the character(Put the $/$ to distinguish the two integers and the character if the number is negative).
Then we have satisfied the condition of exercise 25. Hence we have a result.
