A module M is called epi-retractable if every submodule of M is a homomorphic image of M. Dually, a module M is called co-epi-retractable if it contains a copy of each of its factor modules. In special case, a ring R is called co-pli (resp. co-pri) if RR (resp. RR) is co-epi-retractable. It is proved that if R is a left principal right duo ring, then every left ideal of R is an epi-retractable ...

Let A be a Buchsbaum local ring with the maximal ideal m and let e(A) denote the multiplicity of A. Let Q be a parameter ideal in A and put I = Q : m. Then the equality I = QI holds true, if e(A) = 2 and depth A > 0. The assertion is no longer true, unless e(A) = 2. Counterexamples are given.

The submodules with the property of the title ( a submodule $N$ of an $R$-module $M$ is called strongly dense in $M$, denoted by $Nleq_{sd}M$, if for any index set $I$, $prod _{I}Nleq_{d}prod _{I}M$) are introduced and fully investigated. It is shown that for each submodule $N$ of $M$ there exists the smallest subset $D'subseteq M$ such that $N+D'$ is a strongly dense submodule of $M$ and $D'bi...

The j-multiplicity is an invariant that can be defined for any ideal in a Noetherian local ring (R, m). It is equal to the Hilbert-Samuel multiplicity if the ideal is m-primary. In this paper we explore the computability of the j-multiplicity, giving another proof for the length formula and the additive formula.

In this paper we present a method of obtaining finitely based linear representations of possibly infinitely based semigroups. Let R{x1, x2, . . . } be a free associative algebra over a commutative ring R with the countable set of free generators {x1, x2, . . . }. An endomorphism α of R{x1, x2, . . . } is called a semigroup endomorphism if x1α, x2α, . . . are monomials (i.e. finite products of x...

Certainly 0R ∈ A. Let a, b ∈ A. Then a ∈ An and b ∈ Am for some n,m ∈ N. Without loss of generality, assume n ≤ m. This means An ⊆ Am. So we have a, b ∈ Am. Since Am is a subring, it follows that −a ∈ Am, a + b ∈ Am, and ab ∈ Am. So also −a ∈ A, a + b ∈ A and ab ∈ A. This means A is closed under additive inverses, addition, and multiplication, so A is a subring of R. Let r ∈ R. Since An is an i...

Iterative monads, introduced by Calvin Elgot in the 1970’s, are those ideal monads in which every guarded system of recursive equations has a unique solution. For every ideal monad M we prove that an iterative reflection, i.e., an embedding M ↪−→ M̂ into an iterative monad with the expected universal property, exists. We also introduce the concept of iterativity for algebras for the monad M, fol...

the submodules with the property of the title ( a submodule $n$ of an $r$-module $m$ is called strongly dense in $m$, denoted by $nleq_{sd}m$, if for any index set $i$, $prod _{i}nleq_{d}prod _{i}m$) are introduced and fully investigated. it is shown that for each submodule $n$ of $m$ there exists the smallest subset $d'subseteq m$ such that $n+d'$ is a strongly dense submodule of $m$...

In this paper, we define the notion of minimal prime ideals hoops and investigate some properties them. Then by using annihilators, study relation between annihilators. Also, introduce zero divisors elements prove that set all is a union hoop. Finally, notions maximal hoop, two new as p-ideal m-ideal. them every semi-simple hoop an m-ideal it.

In 1982 Richard P. Stanley conjectured that any finitely generated Zn-graded module M over a finitely generated Nn-graded K-algebra R can be decomposed as a direct sum M = ⊕t i=1 νi Si of finitely many free modules νi Si which have to satisfy some additional conditions. Besides homogeneity conditions the most important restriction is that the Si have to be subalgebras of R of dimension at least...