Users’ signing order is an important factor in multisignature schemes. In fact the signing order often reflects signer’s rank in a signing group. So far, many multisignature schemes, called structured schemes, have been proposed that provide verifiability of the signing order associated with the structure of a group of signers. However, there are not many structured multisignature schemes utili...

Let $R$ be a commutative Noetherian ring with non-zero identity, $fa$ an ideal of $R$, and $X$ an $R$--module. Here, for fixed integers $s, t$ and a finite $fa$--torsion $R$--module $N$, we first study the membership of $Ext^{s+t}_{R}(N, X)$ and $Ext^{s}_{R}(N, H^{t}_{fa}(X))$ in the Serre subcategories of the category of $R$--modules. Then, we present some conditions which ensure the exi...

This article concerns commutative factor rings for ideals contained in the center. A ring $R$ is called CIFC if $R/I$ some proper ideal $I$ of with $I\subseteq Z(R)$, where $Z(R)$ center $R$. We prove that (i) a $R$, $W(R)$ contains all nilpotent elements (hence Köthe's conjecture holds $R$) and $R/W(R)$ reduced ring; (ii) strongly bounded $R/N_*(R)$ $0\neq N_*(R)\subseteq (resp., $N_*(R)$) Wed...

The first part of the paper is concerned to relationship between the sets of associated primes of the generalized $d$-local cohomology modules and the ordinary  generalized local cohomology  modules.  Assume that $R$ is a commutative Noetherian local ring, $M$ and $N$  are  finitely generated  $R$-modules and $d, t$ are two integers. We prove that $Ass H^t_d(M,N)=bigcup_{Iin Phi} Ass H^t_I(M,N)...

Let $R$ be a commutative Noetherian ring. We prove that  over a local ring $R$ every finitely generated $R$-module $M$ of finite Gorenstein projective dimension has a Gorenstein projective cover$varphi:C rightarrow M$ such that $C$ is finitely generated and the projective dimension of $Kervarphi$ is finite and $varphi$ is surjective.

for a finite field $mathbb{f}_q$, the bivariate skew polynomial ring $mathbb{f}_q[x,y;rho,theta]$ has been used to study codes cite{xh}. in this paper, we give some characterizations of the ring $r[x,y;rho,theta]$, where $r$ is a commutative ring. we investigate 2-d skew $(lambda_1,lambda_2)$-constacyclic codes in the ring $r[x,y;rho,theta]/langle x^l-lambda_1,y^s-lambda_2rangle_{mathit{l}}.$ a...

Definition 1.1 (Rings). The algebraic structure “ring” R is a set with two binary operations + and ·, respectively named addition and multiplication, satisfying • (R,+) is an abelian group (i.e. a group with commutative addition), • is associative (i.e. 8a, b, c 2 R, (a · b) · c = a · (b · c)) , • and the distributive law holds (i.e. 8a, b, c 2 R, (a+ b) · c = a · c+ b · c, a · (b+ c) = a · b+ ...

Braces were introduced by Rump to study non-degenerate involutive set-theoretic solutions of the Yang–Baxter equation. To study non-involutive solutions one needs skew braces, a non-commutative analog of braces. In this talk we discuss basic properties of skew braces and how these structures are related to the Yang-Baxter equation. We also discuss interesting connections between skew braces and...

In this paper we propose two KAP(key agreement protocols) using multivariate equations. As the enciphering functions we select the multivariate functions of high degree on non-commutative ring H over finite field Fq. Two enciphering functions are slightly different from the enciphering function previously proposed by the present author. In proposed systems we can adopt not only the quaternion r...