For any operator on integer-valued functions, we say that #P is closed under in context PF#P if, for every f 2 #P, f] belongs to PF #P. For several operators , it is shown that the closure properties of #P under in the above sense is closely related to the relationships between P #PP1] and higher classes such as PH PP and PP PP .

In recent years, the decay η → 3π has received considerable attention from experimental and theoretical side. It is of particular theoretical interest because it allows for the determination of (mu −md). In addition, for many years now theory has had difficulties to understand the slope of the neutral channel Dalitz plot distribution, which in contrast is very well measured. I discuss here the ...

We consider whether or not protein chains in the HP model have unique or few optimal foldings. We solve the conjecture proposed by Aichholzer et al. that the open chain L2k−1 = (HP )(PH) for k ≥ 3 has exactly two optimal foldings on the square lattice. We show that some closed and open chains have unique optimal foldings on the hexagonal and triangular lattices, respectively.

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يتناول هذا البحث مسألة التيار الصوفي التونسي ومواقفه السياسية من السلطة في القرن 15م والقرن 16م. فالتيار تونس لم يكن تيارا تقليديا منعزلا عن الساحة المجتمعية والسياسية، بل كان فاعلا وحيويا. وكان يتمتع بسعة أفق، وبرؤية مختلفة تماما الطرق الصوفية التي ظهرت المشرق العربي. غير أن قد عرف منذ النصف الثاني للقرن 16م انقساما إلى شقين أساسيين: الأول الاجتماعي الذي انتهج أسلوب التهادن مع السياسية، بقدرة ...

and partly results of my Ph. D. student Richard Cleyton. It is a pleasure to thank the Erwin Schrrdinger Institute and the organisers of the program on Holonomy Groups in Diierential Geometry for their kind hospitality.