┄
Wikipedia
A partition of an interval [a,b] on the real line is a finite sequence x0, x1, x2, ..., xn of real numbers such that
a=x₀<x₁<x₂<...<xₙ=b.
Let f:[a,b]￫ℝ be a function defined on an interval [a,b] of the real numbers, ℝ, and
P = {[x⸤0⸥,x⸤1⸥],[x⸤1⸥,x⸤2⸥],...,[x⸤n−1⸥,x⸤n⸥]},
a partition of I, where
a=x₀<x₁<x₂<...<xₙ=b.
┄
