Let IR(G) denote the augmentation ideal of the group algebra R(G) of a group G with coefficients in a commutative ring R . We give a complete description of the third relative dimension subgroup G∩ (1+ IR(K)IR(G)+ I3 R(G)) and the second relative Fox subgroup G ∩ (1 + IR(K)IR(H) + I2 R(G)IR(H)) for any subgroups K and H of G. Mathematical subjects classification: 20C07 (Primary), 20J05 (Seconda...

In this paper, first we study the semi maximal filters in linear $BL$-algebras and we prove that any semi maximal filter is a primary filter. Then, we investigate the radical of semi maximal filters in $BL$-algebras. Moreover, we determine the relationship between this filters and other types of filters in $BL$-algebras and G"{o} del algebra. Specially, we prove that in a G"{o}del algebra, any ...

Let k be a commutative ring and let R be a commutative k−algebra. Given a positive integer n and a R−algebra A one can consider three functors of points from the category CR of commutative R−algebras to the small category of sets. All these functors are representable, namely • RepA represents the functor induced by B → homR(A,Mn(B)), where Mn(B) are the n× n matrices over B, for all B ∈ CR. • t...

Let X be a finite set and let k be a commutative ring. We consider the k-algebra of the monoid of all relations on X, modulo the ideal generated by the relations factorizing through a set of cardinality strictly smaller than Card(X), called inessential relations. This quotient is called the essential algebra associated to X. We then define a suitable nilpotent ideal of the essential algebra and...

‡ Every function on a finite residue class ring D/I of a Dedekind domain D is induced by an integer-valued polynomial on D that preserves congruences mod I if and only if I is a power of a prime ideal. If R is a finite commutative local ring with maximal ideal P of nilpotency N satisfying for all a, b∈R, if ab∈ P then a∈ P k , b∈ P j with k+ j ≥min(n,N), we determine the number of functions (as...

We begin by briefly recalling some of our previous results on the descent algebra of the hyperoctahedral groups Bn. From this we construct a “nice” expression for the generating function of a family of orthogonal idempotents ρkn. More precisely ∑n k=1 ρknx = 1 2nn! ∑ π∈Bn (x−2d(π))↑ Bn π, where d(π) stands for the number of descents of π and (x)↑ Bn =(x+1)(x+3)(x+5)···(x+2n−1). We show that the...

A Heyting algebra is a distributive lattice with implication and a dual $BCK$-algebra is an algebraic system having as models logical systems equipped with implication. The aim of this paper is to investigate the relation of Heyting algebras between dual $BCK$-algebras. We define notions of $i$-invariant and $m$-invariant on dual $BCK$-semilattices and prove that a Heyting semilattice is equiva...

Let R be a (nonzero commutative unital) ring. If I and J are ideals of R such that R/I ⊕R/J is a cyclic R-module, then I + J = R. The rings R such that R/I ⊕R/J is a cyclic R-module for all distinct nonzero proper ideals I and J of R are the following three types of principal ideal rings: fields, rings isomorphic to K ×L for the fields K and L, and special principal ideal rings (R,M) such thatM...