A Mackey formula in the group ring of a Coxeter group

The Cohomology of a Coxeter Group with Group Ring Coefficients

a swot analysis of the english program of a bilingual school in iran

با توجه به جایگاه زبان انگلیسی به عنوان زبانی بین المللی و با در نظر گرفتن این واقعیت که دولت ها و مسئولان آموزش و پرورش در سراسر جهان در حال حاضر احساس نیاز به ایجاد موقعیتی برای کودکان جهت یاد گیری زبان انگلیسی درسنین پایین در مدارس دو زبانه می کنند، تحقیق حاضر با استفاده از مدل swot (قوت ها، ضعف ها، فرصتها و تهدیدها) سعی در ارزیابی مدرسه ای دو زبانه در ایران را دارد. جهت انجام این تحقیق در م...

What Is a Coxeter Group?

Coxeter groups arise in a wide variety of areas, so every mathematician should know some basic facts about them, including their connection to “Dynkin diagrams.” Proofs about these “groups generated by reflections” mainly use group theory, geometry, and combinatorics. This talk will briefly explain: what it means to say that G is a “group generated by reflections” (or, equivalently, that G is a...

On the Center of a Coxeter Group

In this paper, we show that the center of every Coxeter group is finite and isomorphic to (Z2) n for some n ≥ 0. Moreover, for a Coxeter system (W, S), we prove that Z(W ) = Z(W S\S̃) and Z(W S̃ ) = 1, where Z(W ) is the center of the Coxeter group W and S̃ is the subset of S such that the parabolic subgroup W S̃ is the essential parabolic subgroup of (W, S) (i.e. W S̃ is the minimum parabolic subgr...

THE DERIVED GROUP OF A SEIFERT FIBRE GROUP

Every Seifert Fibre Group is the lift of a Fuchsian group to the universal covering group of PSL (2,R). From this, we work out a form of presentation for such a group. With the calculation of the Euler number, we can establish the presentation of the derived group of a Seifert Fibre Group