Question 42
Let $f$ be a function with the following properties:
(i) $f(n)$ is defined for every positive integer $n$;
(ii) $f(n)$ is a positive integer;
(iii) $f(f(m) + f(n)) = m + n$ for all $m$ and $n$.
Find $f(1997)$.
(i) $f(n)$ is defined for every positive integer $n$;
(ii) $f(n)$ is a positive integer;
(iii) $f(f(m) + f(n)) = m + n$ for all $m$ and $n$.
Find $f(1997)$.