Calculs d'invariants primitifs de groupes finis
We introduce in this article a new method to calculate all absolute and relatif primitive invariants of finite groups. This method is inspired from K. Girstmair which calculate an absolute primitive invariant of minimal degree. Are presented two algorithms, the first one enable us to calculate all primitive invariants of minimal degree, and the second one calculate all absolute or relative primitive invariants with distincts coefficients. This work take place in Galois Theory and Invariant Theory. ...
Let be a non-maximal order in a finite algebraic number field with integral closure . Although is not a unique factorization domain, we obtain a positive integer and a family (called a Cale basis) of primary irreducible elements of such that has a unique factorization into elements of for each coprime with the conductor of . Moreover, this property holds for each nonzero when the natural map is bijective. This last condition is actually equivalent to several properties linked...
The notion of the characteristic of rings and its basic properties are formalized [14], [39], [20]. Classification of prime fields in terms of isomorphisms with appropriate fields (ℚ or ℤ/p) are presented. To facilitate reasonings within the field of rational numbers, values of numerators and denominators of basic operations over rationals are computed.
Soient une variété abélienne sur un corps de nombres et son groupe de Mumford–Tate. Soit une valuation de et pour tout nombre premier tel que , soit l’automorphisme de Frobenius (géométrique) de la cohomologie étale -adique de . On montre que si a une bonne réduction ordinaire en , alors il existe tel que, pour tout , soit conjugué à dans . On montre un résultat analogue pour le frobenius de la cohomologie cristalline de la réduction de modulo .
Let be a commutative ring with identity and an ideal of . is said to be - if for every element there is an idempotent such that is a unit and belongs to . A filter of ideals, say , of is Noetherian if for each there is a finitely generated ideal such that . We characterize -clean rings for the ideals , , , and , in terms of the frame of multiplicative Noetherian filters of ideals of , as well as in terms of more classical ring properties.
This text has two parts. The first one is the essentially unmodified text of our 1973-74 seminar on integral dependence in complex analytic geometry at the Ecole Polytechnique with J-J. Risler’s appendix on the Łojasiewicz exponents in the real-analytic framework. The second part is a short survey of more recent results directly related to the content of the seminar.The first part begins with the definition and elementary properties of the order function associated to an ideal of a reduced analytic...
We study when the modifications of the Cohen-Macaulay vertex cover ideal of a graph are Cohen-Macaulay.