It is well-known that a greedy approximation with an integer-valued polymatroid potential function f is H(γ )-approximation of the minimum submodular cover problem with linear cost where γ is the maximum value of f over all singletons and H(γ ) is the γ -th harmonic number. In this paper, we establish similar results for the minimum submodular cover problem with a submodular cost (possibly nonl...

We show that the operational transconductance amplifier (OTA), as the active element in basic bnilding blocks, can be efficiently used for programmable nonlinear continuous-time function synthesis. Two efficient nonlinear function synthesis approaches are presented. The first approach is a ratiossaf approximation and tbe second is a piecewise.linear approach. Test circuits have been fabricated ...

We study four different approximations for finding the profile of discrete solitons in the one-dimensional Discrete Nonlinear Schrödinger (DNLS) Equation. Three of them are discrete approximations (namely, a variational approach, an approximation to homoclinic orbits and a Green-function approach), and the other one is a quasi-continuum approximation. All the results are compared with numerical...