کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9493588 | 1334249 | 2005 | 16 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
On extensions of modules
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موضوعات مرتبط
مهندسی و علوم پایه
ریاضیات
اعداد جبر و تئوری
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
In this paper we study closely Yoneda's correspondence between short exact sequences and the Ext1 group. We prove a main theorem which gives conditions on the splitting of a short exact sequence after taking the tensor product with R/I, for any ideal I of R. As an application, we prove a generalization of Miyata's theorem on the splitting of short exact sequences and we improve a proposition of Yoshino about efficient systems of parameters. We introduce the notion of sparse module and we show that ExtR1(M,N) is a sparse module provided that there are finitely many isomorphism classes of maximal Cohen-Macaulay modules having multiplicity the sum of the multiplicities of M and N. We prove that sparse modules are Artinian. We also give some information on the structure of certain Ext1 modules.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Algebra - Volume 285, Issue 1, 1 March 2005, Pages 383-398
Journal: Journal of Algebra - Volume 285, Issue 1, 1 March 2005, Pages 383-398
نویسندگان
Janet Striuli,