In this paper we show that inverting problems of higher complexity is easier than inverting problems of lower complexity. While inverting Σ i 3CNFSAT is known to be coNP-complete [6] for i = 1 we prove that it remains coNP-complete for i = 2 and is in P for all i ≥ 3. Relatedly, we show that inverting Σ i 3DNFSAT is in P for all i ≥ 1.

The study proposes an inversion method applicable to observations of deglacial land uplift and tilt near the margin of a major Pleistocene ice-sheet. This information allows the determination of the cross-section of the ice-sheet and the calculation of the thickness of the lithosphere. The method is applied to the Pleistocene glaciations in Fennoscandia and Laurentia and yields similar lithosph...

given by (6) can successfully shorten the settling time of h e tracking control at different operation speeds. In our experimental setup the settling time is in the range of 0.50 N 0.65 s for the conveyor belt running between 9.43 N 26.60 c d s . As we have seen, this is a great improvement in the tracking control compared with that where no special care is taken to compensate for the feedback ...

We attach the degenerate signature (n,0,1) to the dual Grassmann algebra of projective space to obtain a real Clifford algebra which provides a powerful, efficient model for euclidean geometry. We avoid problems with the degenerate metric by constructing an algebra isomorphism between the Grassmann algebra and its dual that yields non-metric meet and join operators. We focus on the cases of n=2...