Let F be a subfield of the field of real numbers and let Fn (n ≥ 2) be the n× n matrix algebra over F. It is shown that if Fn is a lattice-ordered algebra over F in which the identity matrix 1 is positive, then Fn is isomorphic to the lattice-ordered algebra Fn with the usual lattice order. In particular, Weinberg’s conjecture is true. Let L be a totally ordered field, and let Ln (n ≥ 2) be the...

let $r$ be a ring‎, ‎and let $n‎, ‎d$ be non-negative integers‎. ‎a right $r$-module $m$ is called $(n‎, ‎d)$-projective if $ext^{d+1}_r(m‎, ‎a)=0$ for every $n$-copresented right $r$-module $a$‎. ‎$r$ is called right $n$-cocoherent if every $n$-copresented right $r$-module is $(n+1)$-coprese-nted‎, ‎it is called a right co-$(n,d)$-ring if every right $r$-module is $(n‎, ‎d)$-projective‎. ‎$r$ ...

If [Formula: see text] is a directed graph and field, the Leavitt path algebra of over naturally graded by group integers We formulate properties which are equivalent with being crossed product, skew ring, or ring respect to this natural grading. state main result so that also characterized in terms pre-ordered Grothendieck text]-group text]. has finitely many vertices, we characterize when str...

the zero-divisor graph of a commutative ring r with respect to nilpotent elements is a simple undirected graph $gamma_n^*(r)$ with vertex set z_n(r)*, and two vertices x and y are adjacent if and only if xy is nilpotent and xy is nonzero, where z_n(r)={x in r: xy is nilpotent, for some y in r^*}. in this paper, we investigate the basic properties of $gamma_n^*(r)$. we discuss when it will be eu...

Let m, e be positive integers, p a prime number, Fpm be a finite field of p elements and R = Fpm [u]/〈u 〉 which is a finite chain ring. For any ω ∈ R and positive integers k, n satisfying gcd(p, n) = 1, we prove that any (1+ωu)-constacyclic code of length pn over R is monomially equivalent to a matrix-product code of a nested sequence of p cyclic codes with length n over R and a p × p matrix Ap...

We study LCD (linear complementary dual) and ACD (additive codes over a noncommutative non-unital ring E with four elements. This is the first attempt to construct ring. show that free are directly related binary codes. introduce E. They include as special case. These facts imply worth studying. In particular, we characterize E-code C in terms of generator matrix G. also define an code E, calle...

Corollary 0.2 is a well-known fact (e.g., it appears in [12, Lemma A.3] and in [3]), but most of its proofs in literature do not generalize to Theorem 0.1. Orzech’s original proof of Theorem 0.1 (with the corrections provided in [2], as the original version was shaky) proceeds by reducing the theorem to the case when A is Noetherian, and then using this Noetherianness in an elegant and yet myst...