Lower Sum

$\begin{figure}\begin{center}\BoxedEPSF{LowerSum.epsf}\end{center}\end{figure}$

For a given function over a partition of a given interval, the lower sum is the sum of box areas $f(x_k^*)\Delta x_k$ using the smallest value of the function ) in each subinterval $\Delta x_k$ .

See also Lower Integral, Riemann Integral, Upper Sum