How to show that integer subtraction is primitive recursive function?
Hello, Apprentice123!
To make it easier (for me), I'll consider positive integers only.
Show that integer subtraction is primitive recursive function.
Consider the subtraction: .$\displaystyle a - b$
Let $\displaystyle a_0 = a$
Then: .$\displaystyle a_n \:=\:a_{n-1} - 1\;\text{ for }n = 1,2,3,\hdots\:b.$
. . The answer is: .$\displaystyle a_b$