Relative convex hulls have been suggested for multigridconvergent surface area estimation. Besides the existence of a convergence theorem there is no efficient algorithmic solution so far for calculating 3D relative convex hulls. This article discusses an approximative solution based on minimum-length polygon calculations. It is illustrated that this approximative calculation also proves (exper...

In this paper it is proved that relative hyperbolicity is an invariant of quasi-isometry. As a byproduct we provide simplified definitions of relative hyperbolicity in terms of the geometry of a Cayley graph. In particular we obtain a definition very similar to the one of hyperbolicity, relying on the existence for every quasi-geodesic triangle of a central left coset of peripheral subgroup.

The main operations in Inductive Logic Programming (ILP) are generalization and specialization, which only make sense in a generality order. In ILP, the three most important generality orders are subsumption, implication and implication relative to background knowledge. The two languages used most often are languages of clauses and languages of only Horn clauses. This gives a total of six diier...

This paper shows that the existence and persistence of ‘overeducation’ can be explained by an extension of the efficiency wage model. When calibrated to fit the amounts of overeducation found in most empirical studies, the model implies that both the relative wage and the relative employment rate of high-skill workers depend inversely on aggregate economic activity. Keeping aggregate employment...

Suppose R is a Bezout domain. In this paper, some necessary and sufficient conditions for the existence of the group inverse for square matrix over R are given, the conditions for the existence of the group inverse of products of matrices are studied, and the equivalent conditions for reverse order law of group inverse of product of matrices are obtained. Also the existence and the representati...