> [!NOTE] Definiton > Let $[a,b]$ be a [[Closed Real Interval|closed real interval]] and $P=\{ x_{0},x_{1},\dots,x_{n} \}$ be a [[Finite Partition of Closed Real Interval|finite partition]] of $[a,b]$ then the mesh size (or norm) of $P$ is given by $||P||=\max_{1 \leq i\leq n} (x_{i}-x_{i-1}).$