  Several techniques were proposed to model the Piecewise linear (PWL)
functions, including convex combination, incremental and multiple choice
methods. Although the incremental method was proved to be very efficient, the
attention of the authors in this field was drawn to the convex combination
method, especially for discontinuous PWL functions. In this work, we modify the
incremental method to make it suitable for discontinuous functions. The
numerical results indicate that the modified incremental method could have
considerable reduction in computational time, mainly due to the reduction in
the number of the required variables. Further, we propose a tighter formulation
for optimization problems over separable univariate PWL functions with binary
indicators by using the incremental method.
