We analyze the vector magnetograms in several well-developed active regions obtained at Huairou Solar Observing Station, National Astronomical Observatories of China, at Mees Solar Observatory, University of Hawaii, and at National Astronomical Observatory of Japan. It is found that there is a basic agreement on the transversal fields among these magnetographs. The observational error (mutual d...

A P4-transversal of a graph G is a set of vertices T which meets every P4 of G. A P4transversal T is called stable if there are no edges in the subgraph of G induced by T . It has been previously shown by Hoàng and Le that it is NP -complete to decide whether a comparability (and hence perfect) graph G has a stable P4-transversal. In the following we show that the problem is NP -complete for ch...

We continue the investigation of validity of Hall’s theorem in the case of the Loeb space L(H) of an internal, uniformly distributed, hyperfinite measure space H = (Ω,A, μ) initiated in1992 by the author. Some new classes of graphs are introduced for which the measure theoretic version of Hall’s theorem still holds.

Contact structures on manifolds and Legendrian and transversal knots in them are very natural objects, born over two centuries ago, in the work of Huygens, Hamilton and Jacobi on geometric optics and work of Lie on partial differential equations. They touch on diverse areas of mathematics and physics, and have deep connections with topology and dynamics in low dimensions. The study of Legendria...

The concept of ‘topological right transversal’ is introduced to study right transversals in topological groups. Given any right quasigroup S with a Tychonoff topology T , it is proved that there exists a Hausdorff topological group in which S can be embedded algebraically and topologically as a right transversal of a subgroup (not necessarily closed). It is also proved that if a topological rig...

Background: Heat cured acrylic resin is the most widely used material in the manufacture ofdenture base, but has mechanical properties weakness (transversal strength and impact strength). Alternative to increase the mechanical properties of acrylic resin is the utilization of reinforcing fibre that is polyethylene fibre that has advantage such as good aesthetic, easy to manipulate and increase ...

Continued investigation of Tamed Frequency Modulation (TFM) has led to an extension, called Generalized Tamed Frequency Modulation (GTFM). The features of GTFM are based on the possibility to select different combinations of parameters which characterize the process of waveform generation. This still allows for the generation of a constant envelope modulated signal with a spectrum similar to TF...

This diploma thesis deals with physical effects in the light output of a vertical cavity surface emitting laser (VCSEL) diode caused by external optical feedback. Such feedback might be induced by reflections from the beginning of a optical waveguide due to a connected refractive index step. The thesis also investigates the influence on waveguide coupled power on opto-electronic waveguide board...

Poisson transversals are submanifolds in a Poisson manifold which intersect all symplectic leaves transversally and symplectically. In this communication, we prove a normal form theorem for Poisson maps around Poisson transversals. A Poisson map pulls a Poisson transversal back to a Poisson transversal, and our first main result states that simultaneous normal forms exist around such transversa...