On a Certain Classification of Rings and Semigroups
نویسنده
چکیده
In his paper Linear equations in non-commutative fields (Ann. of Math. vol. 32 (1931) pp. 463-477) Professor Oystein Ore defines regularity and irregularity of rings and an "order of irregularity" in such a way that regularity becomes irregularity of order 1. Herewith the following problem is proposed: Do irregular rings of order n>\ really exist? If so of what type are they? In this note these questions will be answered. A classification on this line yields nine different types, for which explicit examples are given. This classification turns out to be essentially one of semigroups. For the so-called "ringlike domains," that is, domains having one distributive law only, the position is otherwise and will be treated in detail elsewhere. The first section of this paper contains the general considerations, the second one the examples.
منابع مشابه
On certain semigroups of transformations that preserve double direction equivalence
Let TX be the full transformation semigroups on the set X. For an equivalence E on X, let TE(X) = {α ∈ TX : ∀(x, y) ∈ E ⇔ (xα, yα) ∈ E}It is known that TE(X) is a subsemigroup of TX. In this paper, we discussthe Green's *-relations, certain *-ideal and certain Rees quotient semigroup for TE(X).
متن کاملClassification of Monogenic Ternary Semigroups
The aim of this paper is to classify all monogenic ternary semigroups, up to isomorphism. We divide them to two groups: finite and infinite. We show that every infinite monogenic ternary semigroup is isomorphic to the ternary semigroup O, the odd positive integers with ordinary addition. Then we prove that all finite monogenic ternary semigroups with the same index...
متن کاملA note on the socle of certain types of f-rings
For any reduced commutative $f$-ring with identity and bounded inversion, we show that a condition which is obviously necessary for the socle of the ring to coincide with the socle of its bounded part, is actually also sufficient. The condition is that every minimal ideal of the ring consist entirely of bounded elements. It is not too stringent, and is satisfied, for instance, by rings of ...
متن کاملExamples of non-quasicommutative semigroups decomposed into unions of groups
Decomposability of an algebraic structure into the union of its sub-structures goes back to G. Scorza's Theorem of 1926 for groups. An analogue of this theorem for rings has been recently studied by A. Lucchini in 2012. On the study of this problem for non-group semigroups, the first attempt is due to Clifford's work of 1961 for the regular semigroups. Since then, N.P. Mukherjee in 1972 studied...
متن کاملCommuting $pi$-regular rings
R is called commuting regular ring (resp. semigroup) if for each x,y $in$ R there exists a $in$ R such that xy = yxayx. In this paper, we introduce the concept of commuting $pi$-regular rings (resp. semigroups) and study various properties of them.
متن کامل