=+14.6. 12.31 A Borel function satisfying Cauchy's equation [A20] is automatically bounded in some interval and hence satisfies f(x) =xf(1). Hint: Take K large enough that A[x: x > s, If(x)| ≤ K] > 0. Apply Problem 12.3 and conclude that f is bounded in some interval to the right of 0.