摘要:

TheJ2andJ3radicals for zerosymmetric Γ-near-rings were recently defined by the author. In the present paper we define theJ2(0)andJ3(0)radicals for arbitrary Γ-near-rings. These radicals are sirmlar to corresponding ones which were recently defined by Veldsman for near-rings. LetMbe a r-near-ring with left operator near-ringL.ThenJκ(0)(L)+=Jκ (0)(M),k. = 2,3. If A is an ideal ofM, thenJκ (0)(A) ⊆Jκ (o)(M) ∩A, with equality whenk= 3 andAis left invariant.J3(0)is a Kurosh-Amitsur radical in the variety of Γ-near-rings.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631631

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Nilpotent and solvable ideals are defined and investigated in categories. The relation between the prime radical and the sum of the solvable ideals (which is also a radical) is discussed in categories. For example: If an object satisfies the maximal condition for ideals, then the prime radical is equal to the sum of the solvable ideals. Certain generalizations of theorems in rings, groups, Lie algebras, etc. are also proven, for example: An ideal α:I→Ais semiprime if and only ifA/Icontains no non-zero nilpotent ideals.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631632

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The Σλ-calculus is an extension of an applied λ-calculus designed to abstract parallel and non-deterministic function application evaluation. The abstraction is extended to include Landin's closure, and constant terms and a special form of the conditional allows the regular logics to be developed along the lines of the Hilbert-Ackermann approach. The regular logics are used to characterize derived conditionals in extensions to Dijkstra's weakest preconditions. It is shown that various styles of programming—top-down, bottom-up, recursive and iterative—axe expressible in the Σλ-calculus. Lists and streams are found to be useful in expressing time-dependent behaviour of computational systems. An approximate Church-Rosser Theorem is given.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631633

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

We describe approximations of certain fibres and cofibres respectively which are Eckmann-Hilton dual to each other and we derive from them new exact sequences for homotopy groups and (co)- homology groups in the metastable range.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631634

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Secondary structure of an exact sequence of Maya-Vietoris type associated to a simply-connected homotopy pullback is exploited to yield a technique for computing its higher homotopy groups. The information required consists of the homotopy groups of the original spaces, the homomorphisms induced by the given maps and certain matrix Toda brackets.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631635

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

IfRis a commutative ring with identity andt1,t2,…,tn, are transcendental overRsuch that no tiis algebraic over the ringR[t1,…,t1-1,ti+1,…,tn] it is proved that there exists a minimal prime idealPinRsuch that dimR+1≤ dimR[t1,…,tn] = dimR[t1,…,tn]/P[t1,…,tn]. This equality is used to prove results for R[t1,…tnsimilar to those holding for the integral domain(R/P)[t1,…,tn] with 31,…t1,…,tnindeterminates overR/P.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631636

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Structure theorems are obtained for certain radical classes of rings (including the Brown-McCoy radical class, the class of λ-rings, the class ofE5-rings, the class ofE6-rings and the class off-regular rings) by generalizing the concept of a prime ideal.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631637

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

The concept of torsion-complete abelian groups has already been generalized to modules Over domains. In this note recent results onR-completeness for modules over domains with one-dimensional quotient field are used to give characterizations for torsion-completeness over these domains and to study direct decompositions of torsion-complete modules.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631638

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

摘要:

Eklof-Fuchs [3] have shown that over an arbitrary valuation domainR, the modulesBwhich satisfy Ext 1/R (B,T) = 0 for all torsionR-modulesTare precisely the freeR-modules. Here we modify the problem and describe allR-modulesBfor which Ext 1/R (B, T) vanishes for all bounded and for all divisible torsionR-modulesT.It is well known that if R is a descrete rank one valuation domain then all torsion—freeR-modulesBhave this property.

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631639

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor

ISSN:1607-3606    

DOI:10.1080/16073606.1991.9631640

出版商:Taylor & Francis Group    

年代:1991

数据来源: Taylor