Gray & Hervella gave a classification of almost Hermitian structures (g, I) into 16 classes. We systematically study the interaction between these classes when one has an almost hyper-Hermitian structure (g, I, J,K). In general dimension we find at most 167 different almost hyper-Hermitian structures. In particular, we obtain a number of relations that give hyperKäher or locally conformal hyper...

The well-known fuzzy c-means algorithm is an objective function based fuzzy clustering technique that extends the classical k-means method to fuzzy partitions. By replacing the Euclidean distance in the objective function other cluster shapes than the simple (hyper-)spheres of the fuzzy c-means algorithm can be detected, for instance ellipsoids, lines or shells of circles and ellipses. We propo...

Perfect 1-error correcting codes C in the hyper cube Zn 2 are considered. The possibilities for the number γ(C) of code words in a k-face γ of the hyper cube are discussed. It is shown that the possibilities for the number γ(C) depend on the dimension of the face γ, the rank of C and the dimension of the kernel of C. Especially we get an answer to a question of Sergey V. Avgustinovich whether t...

We consider fundamental properties of weak interlaced bilattices and give a characterization theorem of them, that is, for any weak interlaced bilattice W there exists a bounded lattice L such that W can be embedded into a typical weak interlaced bilattice K(L). Hence, any interlaced bilattice can be embedded into the weak interlaced bilattice K(L) for some lattice L.

We introduce a new obstruction to weak approximation related to non-abelian coverings of a proper and smooth variety X deened over a number eld k. It provides some counterexamples to weak approximation which are not accounted for by the Manin obstruction, for example bielliptic surfaces. 0. Introduction Let X be a smooth and proper algebraic variety over a number eld k and k be the set of place...

We use the fusion calculus, a generalization and simpliication of the-calculus, to model concurrent constraint programming. In particular we encode three basic variants of the-calculus, which is a foundational calculus for the concurrent constraint programming language Oz. Using a new reduction-based semantics and weak barbed congruences for the fusion calculus we formally establish an operatio...