Ein “affiner” Beweis des Satzes von v. Staudt—Schleiermacher

The Theorem ofv. Staudt-Schleiermacher asserts that a projective incidence plane is pappian if every projectivity with 5 fixed points is the identity.Schleiermacher's original proof needs different treatments for a lot of cases. We give a simpler proof based on the fact that Desargues' and Pappos' theorems hold in a projective plane if this is true for some affine specializations.

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Mit 8 Abbildungen     

Some numerical calculations on high field superconductivity

Numerical calculations are presented for the field dependence of critical currents in high field superconductors. The computations are done under two simplifying assumptions, namely that the fluxoids are pinned strongly enough so that flux creep and flux flow does not have to be taken into account, and that spin orbital interaction can be neglected. Only the zero temperature limit is considered. Furthermore, a diagram is calculated with the help of which the following three fields can be read off easily for a given sample: the supercooling and superheating critical field and the field for which the energies in the normal and superconducting state are equal.     

Eine Restgliedabschätzung in der Erneuerungstheorie

Ohne Zusammenfassung