An additive category in which each object has a Krull-Remak-Schmidt decomposition—that is, finite direct sum decomposition consisting of objects with local endomorphism rings—is known as Krull-Schmidt category. A Hom-finite is an for there commutative unital ring k, such that Hom-set length k-module. The aim this note to provide proof Krull-Schmidt, if and only it split idempotents, indecomposa...

It is shown that the Baer–Kaplansky Theorem can be extended to all abelian groups provided rings of endomorphisms are replaced by trusses corresponding heaps. That is, every group determined up isomorphism its endomorphism truss and between two associated some [Formula: see text] induced an element from text]. This correspondence then modules over a ring considering heaps modules. proved heap m...

In this paper we introduce the notion of e-gH modules which is a proper generalization Hopfian and defined as, module called if, any surjective -endomorphism has an e-small kernel, ring e-gH. We give some characterizations properties modules.

We present a generalization to genus 2 of the probabilistic algorithm in Sutherland [28] for computing Hilbert class polynomials. The improvement over the algorithm presented in [5] for the genus 2 case, is that we do not need to find a curve in the isogeny class with endomorphism ring which is the maximal order: rather we present a probabilistic algorithm for “going up” to a maximal curve (a c...

We recall that a ring R is called near pseudo-valuation ring if every minimal prime ideal is a strongly prime ideal. Let R be a commutative ring, σ an automorphism of R. Recall that a prime ideal P of R is σ-divided if it is comparable (under inclusion) to every σ-stable ideal I of R. A ring R is called a σ-divided ring if every prime ideal of R is σ-divided. Also a ring R is almost σ-divided r...

Let (R,m) denote an n-dimensional Gorenstein ring. For an ideal I ⊂ R of height c we are interested in the endomorphism ring B = HomR(H c I (R),H c I (R)). It turns out that B is a commutative ring. In the case of (R, m) a regular local ring containing a field B is a Cohen-Macaulay ring. Its properties are related to the highest Lyubeznik number l = dimk Ext d R(k, H c I (R)). In particular R ≃...

For an infinity of number rings we express stable motivic invariants in terms topological data determined by the complex numbers, real and finite fields. We use this to extend Morel's identification endomorphism ring sphere with Grothendieck-Witt quadratic forms deeper base schemes.

Assuming the Mumford–Tate conjecture, we show that center of endomorphism ring an abelian variety defined over a number field can be recovered from appropriate intersection fields obtained its Frobenius endomorphisms. We then apply this result to exhibit practical algorithm compute center.

We present a generalization to genus 2 of the probabilistic algorithm of Sutherland for computing Hilbert class polynomials. The improvement over the Bröker-Gruenewald-Lauter algorithm for the genus 2 case is that we do not need to find a curve in the isogeny class whose endomorphism ring is the maximal order; rather, we present a probabilistic algorithm for “going up” to a maximal curve (a cur...

The paper studies the following question: Given a ring R, when does the zero-divisor graph (R) have a regular endomorphism monoid? We prove if R contains at least one nontrivial idempotent, then (R) has a regular endomorphism monoid if and only if R is isomorphic to one of the following rings: Z2 × Z2 × Z2; Z2 × Z4; Z2 × (Z2[x]/(x)); F1 × F2, where F1, F2 are fields. In addition, we determine a...