We show that the continuous limit of a wide natural class of the right-invariant discrete Lagrangian systems on the Virasoro group gives the family of integrable PDE's containing Camassa-Holm, Hunter-Saxton and Korteweg-de Vries equations. This family has been recently derived by Khesin and Misio lek as Euler equations on the Virasoro algebra for H 1 α,β-metrics. Our result demonstrates a unive...

In complex task domains, such as games, students may exceed their teachers. Such tasks afford diverse means to tradeoff one type of performance for another, combining task elements in novel ways to yield method variations and strategy discoveries that, if mastered, might produce large or small leaps in performance. For the researcher interested in the development of extreme expertise in the wil...

Olomouc, nowadays a city with 100,000 inhabitants, has always been considered as one of the most prominent Czech cities. It is a social and economical centre, which history started just about the 11th century. The present appearance of the city has its roots in the 18th century, when the city was almost razed to the ground after the Thirty years’war and a great fire in 1709. After that, the cit...

The paper looks into to the work of modern Iranian calligrapher and artist Bahman Panahi. On example his works, one can see dynamism art calligraphy. This type Muslim continues develop actively and, in combination with other types, such as ornament, music or graffiti, gives rise new interesting directions. In Panahi, calligraphy is so naturally combined that himself refers works genre musicalli...

For many years urban commentators have discussed the costs and benefits of urban authorities adopting counter-terrorism measures in the face of real or perceived terrorist threats (see, for example, Boal, 1969; Brown, 1985; Davis, 1992; Pawley, 1998; Graham, 2002). Some of the most historically explicit examples of such measures were seen in Northern Ireland in the early 1970s and 1980s where `...