کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4587608 | 1334151 | 2008 | 21 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Finite index supergroups and subgroups of torsionfree abelian groups of rank two
دانلود مقاله + سفارش ترجمه
دانلود مقاله ISI انگلیسی
رایگان برای ایرانیان
موضوعات مرتبط
مهندسی و علوم پایه
ریاضیات
اعداد جبر و تئوری
پیش نمایش صفحه اول مقاله

چکیده انگلیسی
Every torsionfree abelian group A of rank two is a subgroup of Q⊕Q and is expressed by a direct limit of free abelian groups of rank two with lower diagonal integer-valued 2×2-matrices as the bonding maps. Using these direct systems we classify all subgroups of Q⊕Q which are finite index supergroups of A or finite index subgroups of A. Using this classification we prove that for each prime p there exists a torsionfree abelian group A satisfying the following, where A⩽Q⊕Q and all supergroups are subgroups of Q⊕Q:(1)for each natural number s there are s-index supergroups and also s-index subgroups;(2)each pair of distinct s-index supergroups are non-isomorphic and each pair of distinct s-index subgroups are non-isomorphic.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Algebra - Volume 319, Issue 9, 1 May 2008, Pages 3567-3587
Journal: Journal of Algebra - Volume 319, Issue 9, 1 May 2008, Pages 3567-3587