摘要:

In an earlier paper [l0], the first author determined the projective characters of rotation subgroups W+(Φ) of the exceptional Weyl groups W(Φ), Φ=El(l=6,7,8). For the case Φ=F4, only those characters of W+(F4) whose factor set α corresponds to the basic spin representations determined in [9] were obtained. In the present paper we obtain the irreducible characters of W+(F4)corresponding to the remaining classes of factor sets, thereby completing the work in [lo]. We also give explicit constructions for some of the projective representations.

ISSN:0092-7872    

DOI:10.1080/00927879208824546

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879208824547

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879208824548

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

摘要:

Let G be a finite group, n an integer and P a field; we say that G ∈ Rn(P) if for any irreducible representation X of G there exists a proper subgroup H (depending on X) and an irreducible representation ξ of H which is a component of X|H with multiplicity ≤ n. We prove that G ∈ Rn(P) for an algebraically closed field P provided S ∈ Rn(P) for the universal central extensions S of all nonabelian simple quotients of G. We also prove that the universal central extensions of all projective special linear groups PSL(m.,q), of alternating groups Amand Suzuki groups Sz(q) belong to R1(C).

ISSN:0092-7872    

DOI:10.1080/00927879208824549

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879208824550

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879208824551

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879208824552

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

ISSN:0092-7872    

DOI:10.1080/00927879208824553

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

摘要:

Let A be a commutative ring with 1/2 ∈ A. in the spirit of [Gro], by means of a quadratic flag bundle, we obtain Stieffel-Whitney classesfor the Witt-Grothendieck group of quadratic modules of constant rank, with values in the group of global sections of the sheaf associated with kj=Kj/2Kj, the Milnor Kj-group mod 2.

ISSN:0092-7872    

DOI:10.1080/00927879208824554

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor

摘要:

Let A → B be an injective ring morphism. The The Traverso-Swan's seminormalization of A in B can be considered as the greatest subring C of B , such that the ring morphism A → C is spectrally bijective, with isomorphic residue field extensions. Assume now that A and B are Noetherian, Mori, integral domains, then T. Sugatani and K. Yoshida defined the t-closure of A in B as the greatest subring C of B such that the ring morphism A → C has isomorphic residue field extensions and is spectrally surjective. Following Swan's ideas about seminormalization, we have been able to delete the above hypothesis. We thus have obtained a general theory of t-closedness. Jnfra-integral morphisms in this work areanalogous with subintegral morphisms of Swan's work.

ISSN:0092-7872    

DOI:10.1080/00927879208824555

出版商:Marcel Dekker, Inc.    

年代:1993

数据来源: Taylor