- If you have recurrence form below: - $T(n)$ is the work to solve a problem of size $n$ - $T(n) = aT(n/b) + O(n^d$) where $a > 0 , b > 1 , d \geq 0$ - $T(n)$ $=$ - $O(n^d)$ if $d > log_b(a)$ - $O(n^d log(n))$ if $d = log_b(a)$ - $O(n^{log_b(a)})$ if $d < log_b(a)$