The main contents of the thesis consist of two independent parts . one is the characterization of weak i sequences in terms of ext functors . we prove that the existence of such sequence and the length of a maximal weak / sequence can be expressed as some vanishing properties of ext functors 本文主要研究工作由兩個(gè)獨(dú)立的部分組成,其中一部分是利用ext函子來刻畫弱i序列,并且證明了這個(gè)序列的存在性,以及極大弱i序列具有同樣的長度。
百科解釋
在同調(diào)代數(shù)中,Ext 函子是 Hom 函子的導(dǎo)函子。此函子首見于代數(shù)拓?fù)?,但其?yīng)用遍布許多領(lǐng)域。