اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدThe realization problem for von Neumann regular rings
301
0
0.0
(
0
)
تأليف
Pere Ara
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
We survey recent progress on the realization problem for von Neumann regular rings, which asks whether every countable conical refinement monoid can be realized as the monoid of isoclasses of finitely generated projective right $R$-modules over a von Neumann regular ring $R$.
قيم البحث
اقرأ أيضاً
In this note, we show that any epimorphism originating at a von Neumann regular ring (not necessary commutative) is a universal localization. As an application, we prove that the Telescope Conjecture holds for the unbounded derived categories of von Neumann regular rings (not necessary commutative).
Flat modules play an important role in the study of the category of modules over rings and in the characterization of some classes of rings. We study the e-flatness for semimodules introduced by the first author using his new notion of exact sequence
s of semimodules and its relationships with other notions of flatness for semimodules over semirings. We also prove that a subtractive semiring over which every right (left) semimodule is e-flat is a von Neumann regular semiring.
Let $R$ be a ring and $S$ a multiplicative subset of $R$. An $R$-module $T$ is called uniformly $S$-torsion provided that $sT=0$ for some $sin S$. The notion of $S$-exact sequences is also introduced from the viewpoint of uniformity. An $R$-module $F
$ is called $S$-flat provided that the induced sequence $0rightarrow Aotimes_RFrightarrow Botimes_RFrightarrow Cotimes_RFrightarrow 0$ is $S$-exact for any $S$-exact sequence $0rightarrow Arightarrow Brightarrow Crightarrow 0$. A ring $R$ is called $S$-von Neumann regular provided there exists an element $sin S$ satisfies that for any $ain R$ there exists $rin R$ such that $sa=ra^2$. We obtain that a ring $R$ an $S$-von Neumann regular ring if and only if any $R$-module is $S$-flat. Several properties of $S$-flat modules and $S$-von Neumann regular rings are obtained.
For a division ring $D$, denote by $mathcal M_D$ the $D$-ring obtained as the completion of the direct limit $varinjlim_n M_{2^n}(D)$ with respect to the metric induced by its unique rank function. We prove that, for any ultramatricial $D$-ring $math
cal B$ and any non-discrete extremal pseudo-rank function $N$ on $mathcal B$, there is an isomorphism of $D$-rings $overline{mathcal B} cong mathcal M_D$, where $overline{mathcal B}$ stands for the completion of $mathcal B$ with respect to the pseudo-metric induced by $N$. This generalizes a result of von Neumann. We also show a corresponding uniqueness result for $*$-algebras over fields $F$ with positive definite involution, where the algebra $mathcal M_F$ is endowed with its natural involution coming from the $*$-transpose involution on each of the factors $M_{2^n}(F)$.
Given a subdirectly irreducible *-regular ring R, we show that R is a homomorphic image of a regular *-subring of an ultraproduct of the (simple) eRe, e in the minimal ideal of R; moreover, R (with unit) is directly finite if all eRe are unit-regular
. Finally, unit-regularity is shown for every member of the variety generated by artinian *-regular rings (endowed with unit and pseudo-inversion).
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
