Some applications of the theory of blocks of characters of finite groups IV
Some applications of the theory of blocks of characters of finite groups IV
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DOI:
10.1016/0021-8693(71)90006-8
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发表时间:
1964-12
影响因子:
0.9
通讯作者:
R. Brauer
中科院分区:
文献类型:
--
作者:
R. Brauer
In a series of papers of the same title [3], some applications have been given of the theory of blocks of characters of finite groups. This work will be continued here and in a subsequent paper. In Section II, the notation is explained. Some presupposed results are stated, and a number of lemmas are proved. In Section III, the kernel of a block is studied. This extends results proved in [31] for the principal block. Again, Section IV deals with extensions of Theorem 3 of [31]. We are concerned with certain types of blocks of full defect. Methods of this type play an important role in the investigation of finite groups with quasidihedral and wreathed Sylow 2-subgroup, cf.[I]. In particular, they will be needed in a continuation of [I], in order to develop the necessary character theory for the latter type of groups.It had already been shown in [31], that for a given prime p and a given defect d, the p-blocks of defect d of arbitrary finite groups fall into a finite number of ‘Yypes.” This investigation is covered in a more precise form and continued in Section V. In a way, the results provide a justification for a further study of blocks. There are cases in which a full discussion of the possible types can be given. We deal here with the case p= 2, d= 2 in Section VII and use the results to obtain a formula for the order of G. This formula is needed in [l]. There are other cases in which a full discussion of the blocks can be given. This will be done elsewhere. The preceding Section VI contains some results on blocks which are needed in Section VII. We can also improve results of [411] on the height of the characters in blocks with abelian defect groups. Finally, Section VIII contains some rather simple results on contragredient blocks. These too are needed in [I].