Search
Search results for
We found
41 results for you
-
Higher Derivations and a Theorem By Herstein
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Miguel Ferrero Claus HaetingerIn this paper we extend to the higher derivations a well-known result proved by Herstein concerning derivations in prime rings. We prove results which imply that every Jordan higher derivation of a 2-torsion-free semiprime ring is a higher derivation. -
A Characterization of the Prime Closed Filter Compactification of a Topological Space
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: H.L. Bentley H. HerrlichThe prime compactification whose points are the prime closed filters can be defined for a general topological space and is naturally functorial. We derive several properties of this compactification and present a characterization. -
A note on * μ -rings
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: H. France-Jackson H.J. Le RouxWe introduce and investigate the concept of * μ -rings which is a generalization of *-rings defined and studied in [4], [5], [6], [7] and [10]. This lets us generalize many important results valid for *-rings and obtain a useful... -
A Pointfree Study of Bases For Spaces Of Minimal Prime Ideals
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Melvin Henriksen Joanne Walters-WaylandLet C (X) denote the ring of all real-valued continuous functions on a topological space X, and mX its space of minimal prime ideals with the hull-kernel topology. It has a base consisting of clopen sets and which contains the... -
Irreducibility in Pointfree Topology
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Themba DubeIrreducible spaces have been studied in topology by several authors. A. H. Stone introduced semi-irreducibility as a way of studying hereditarily compact spaces. In this paper we investigate these concepts in the context of frames. -
A generalization of 2-primal near-rings
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: N. Argac N.J. GroenewaldIn this note we generalize the notion of 2-primal and nil-primal nearrings. For a Hoehnke radical ρ we introduce the notion of ρ–primal near-rings. 2-primal and nil-primal near-rings are examples of ρ–primal near-rings. We show that many of the results... -
(Φ, M)–extensions of near-rings
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Mark FaragIn this paper, we define and study a generalization of matrix, polynomial, and group near-rings. New results on ideal essentiality and lying over are obtained. -
On left (right) strong and left (right) hereditary radicals
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Halina France-JacksonE.R. Puczylowski proved that the lower radical l M generated by a homomorphically closed class M of rings is left strong if M satisfies the following three conditions: (1) If L ∈ M is a nonzero left ideal of... -
Different nil radicals for near-rings
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: N.J GroenewaldIt is well known that there are a number of different nonequivalent definitions of a prime near-ring. In this paper we show that this give rise to a number of different upper nil radicals which all coincide with the usual... -
On Russell and Anti Russell-Cardinals
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Horst Herrlich --- , Germany Kyriakos Keremedis --- Department of Mathematics, Greece Eleftherios Tachtsis --- Department of Statistics and Actuarial-Financial Mathematics, GreeceIn the absence of the Axiom of Choice we study countable families of 2-element sets with no choice functions which either have infinite subfamilies with a choice function or no infinite subfamilies with a choice function. -
An Algebraic Characterization of Blumberg Spaces
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: M.R. Ahmadi Zand --- Department of Mathematics, IranLet X be a topological space and let C(X) be the ring of continuous real-valued functions on X. We study T′(X) as an over-ring of C(X), where T′(X) denotes the set of all real-valued functions on X such that for... -
Pointfree Aspects of the Td Axiom of Classical Topology
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Bernhard Banaschewski --- Department of Mathematics and Statistics, Canada Ale[sbreve] Pultr --- Department of Applied Mathematics and ITI, MFF, Czech RepublicAbstraction from the condition defining To-spaces leads to the following notion in an arbitrary frame L: a filter F in L is called slicing if it is prime and there exist a, b e L such that a £ F,... -
On Prime and Semiprime Near-Rings with Generalized Derivation
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Öznur Gölbaşi --- Department of Mathematics, TurkeyLet N be a left near-ring and S be a nonempty subset of N. A mapping F from N to N is called commuting on S if [F(x),x] = 0 for all x € S. The mapping F is called... -
Age, growth and reproductive biology of the blue shark Prionace glauca in South African waters
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: KA Jolly --- Zoology Department, South Africa C da Silva --- Fisheries Research, Department of Agriculture, South Africa CG Attwood --- Zoology Department, South AfricaThe age, growth and reproductive biology of the blue shark Prionace glauca from South African waters were assessed using 205 specimens, ranging in total length (TL) from 72 to 313 cm. Greater number of males (120) than females (85) were... -
On Compositeness in Multicompositions
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Temba ShonhiwaThe paper investigates the structure of the highly composite multicomposition function gm (n) which enumerates the number of m-compositions of n into relatively prime positive summands. Among other results, we generalize a known result by establishing that the lcm -
Microsatellite markers for population genetic studies of the rock firefinch, Lagonosticta sanguinodorsalis
Item type: Journal Article • Journal: African Zoology • Authors: Jacinta Abalaka --- Department of Genetics, South Africa Bengt Hansson --- Department of Biology, SwedenWe identified the first set of microsatellites for use in the rock firefinch (Lagonosticta sanguinodorsalis). First, we tested existing passerine microsatellite loci for cross-species amplification success in a small sample of rock firefinches and identified 10 loci that were seemingly... -
Effect of the subprime mortgage crisis on a leading emerging market
Item type: Journal Article • Journal: Investment Analysts Journal • Authors: Jun Sik Kim --- Division of International Trade, Korea Doojin Ryu --- College of Economics, KoreaThis study examines how the US subprime mortgage crisis affects the behaviour of the Korean stock and futures market and how the futures traders react to the shocks related to the crisis. Analysing a unique and high-quality daily data set... -
A note on non-monogenity of number fields arised from sextic trinomials
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Anuj Jakhar --- Indian Institute of Technology (IIT), India Sumandeep Kaur --- Panjab University, IndiaLet K = Q (θ) be an algebraic number field with θ a root of an irreducible polynomial f(x) = x 6 + axm + b belonging to ℤ[x] and 1 ≤ m ≤ 5. Let OK be the... -
Histological assessment of selected tissues in tigerfish (Hydrocynus vittatus Castelnau, 1861) from the Sanyati Basin, Lake Kariba, Zimbabwe: a DDT-sprayed area
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: N Mabika --- Department of Zoology, South Africa M Barson --- Department of Zoology, South Africa C van Dyk --- Department of Zoology, South Africa A Avenant-Oldewage --- Department of Zoology, South AfricaA pilot investigation was conducted in 2014 in the Sanyati Basin of Lake Kariba to ascertain whether long-term DDT spraying in the Kariba catchment had a negative effect on fish health. The aim was to assess the health of tigerfish,... -
Genomic resources for the spotted ragged-tooth shark Carcharias taurus
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JD Klein --- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, South Africa AE Bester-van der Merwe --- Molecular Breeding and Biodiversity Group, Department of Genetics, South Africa ML Dicken --- KwaZulu-Natal Sharks Board, South Africa A Emami-Khoyi --- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, South Africa KL Mmonwa --- KwaZulu-Natal Sharks Board, South Africa PR Teske --- Centre for Ecological Genomics and Wildlife Conservation, Department of Zoology, South AfricaGenomic data can be a useful tool in the management and conservation of biodiversity. Here, we report the development of genomic resources for the spotted ragged-tooth shark Carcharias taurus using genome-wide DNA data from Illumina next-generation sequencing. We explored two... -
A pilot study on the use of DNA metabarcoding for diet analysis in a montane amphibian population from North Africa
Item type: Journal Article • Journal: African Journal of Herpetology • Authors: Ana Pereira --- Universidade do Porto, Portugal Mohamed Amine Samlali --- Cadi Ayyad University, Morocco Abderrahim S’Khifa --- Cadi Ayyad University, Morocco Tahar Slimani --- Cadi Ayyad University, Morocco D James Harris --- Universidade do Porto, PortugalAlthough dietary studies are essential to design effective conservation strategies for amphibians, non-invasive studies using microscopy assessment of faecal material are known to have limitations. We assessed the use of DNA metabarcoding to determine diet in the Moroccan painted frog... -
On S-1-absorbing prime and weakly S-1-absorbing prime ideals
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Najib Mahdou --- University S.M. Ben Abdellah Fez, Morocco Abdeslam Mimouni --- King Fahd University of Petroleum & Minerals, Saudi Arabia Youssef Zahir --- Mohammed-V University in Rabat, MoroccoLet A be a commutative ring with identity and S be a multiplicative subset of A. In this paper, we introduce and study the notions of S-1-absorbing and weakly S-1-absorbing prime ideals as generalizations of the notion of prime ideals... -
An allele-specific PCR assay for detection of mutations that confer benzimidazole resistance and zoxamide sensitivity in Phyllosticta citricarpa
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Beatrix Coetzee --- Stellenbosch University, South Africa Elma Carstens --- Citrus Research International (Pty) Ltd, South Africa Gerhardus C Schutte --- Avima (Pty) Ltd, South Africa Elaine Basson --- Citrus Research International (Pty) Ltd, South Africa Mia J Groeneveld --- Stellenbosch University, South Africa Tankiso Mpholo --- Land Reform and Rural Development, South Africa Providence Moyo --- Citrus Research International (Pty) Ltd, South Africa Jessica C Winn --- Stellenbosch University, South Africa Paul H Fourie --- Citrus Research International (Pty) Ltd, South Africa Aletta E Bester van der Merwe --- Stellenbosch University, South AfricaPhyllosticta citricarpa is the causative agent of citrus black spot (CBS), a cosmetic fungal disease that has been reported in most of the citrus-growing regions of the world. The occurrence of CBS in orchards is predominantly controlled by the application... -
On the categorical behaviour of locales and D-localic maps
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Igor Arrieta --- University of Coimbra, Portugal Javier Gutiérrez García --- University of the Basque Country UPV/EHU, SpainIt was shown by Banaschewski and Pultr that the classical adjunction between Top and Loc restricts to an adjunction between the category Top D of TD -spaces and their continuous maps, and the category Loc D of all locales and... -
Euclidean polynomials for certain arithmetic progressions and the multiplicative group of
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Kadri İlker Berktav --- Institute of Applied Mathematics, Middle East Technical University, Turkey Ferruh Özbudak --- Middle East Technical University, TurkeyLet f(x) be a polynomial with integer coefficients. We say that the prime p is a prime divisor of f(x) if p divides f(m) some integer m. For each positive integer n, we give an explicit construction of a polynomial... -
On common index divisor and monogenity of certain number fields defined by trinomials X 6 + AX + B
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Lhoussain El Fadil --- Sidi mohamed ben Abdellah University, MoroccoFor a number field K defined by a trinomial F (x) = x 6 + ax + b ∈ ℤ[x], Jakhar and Kumar gave some necessary conditions on a and b, which guarantee the non-monogenity of K [25]. In this... -
The number fields that are O*-fields II
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Jingjing Ma --- University of Houston-Clear Lake, USA Ashley Martinez --- University of Houston-Clear Lake, USAAn O* -field is a field K for which each partial order with respect to which K is a partially ordered field can be extended to a total order with respect to which K is a totally ordered field. When... -
On the index divisors and monogenity of number fields defined by x 5 + ax 3 + b
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Lhoussain El Fadil --- Sidi Mohamed Ben Abdellah University, MoroccoThe main goal of this paper is to provide a complete answer to the Problem 22 of Narkiewicz[24] for any quintic number field K generated by a complex root α of a monic irreducible trinomial F(x) = x 5 +... -
The influence of TI-property and subnormality of self-centralizing subgroups of non-prime-power order on the structure of finite groups
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Jiangtao Shi --- Yantai University, P.R. China Na Li --- Beijing Jiaotong University, P.R. ChinaWe obtain a complete classification of the structure of finite groups in which every self-centralizing subgroup of non-prime-power order is a TI-subgroup or a subnormal subgroup. -
Some questions on partially ordered rings – a survey
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Jingjing Ma --- University of Houston-Clear Lake, USAThis survey provides a brief overview and new developments on some questions in the area of partially ordered and lattice-ordered rings and algebras. -
Truncated vector lattices: A Maeda-Ogasawara type representation
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Karim Boulabiar --- Université de Tunis El Manar, Tunisia Rawaa Hajji --- Université de Tunis El Manar, TunisiaLet L be a truncated Archimedean vector lattice whose truncation is denoted by *. In a recent paper, we proved that there exists a locally compact Hausdorff space X such that L is a lattice isomorphic with a truncated vector... -
Certain results on gradient almost η-Ricci-Bourguignon soliton
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Santu Dey --- Bidhan Chandra College, IndiaThe present research article deals with the study of almost η-Ricci-Bourguignon soliton and gradient almost η-Ricci-Bourguignon soliton on almost Kenmotsu manifolds. It is shown that if the metric of a Kenmotsu manifold M 2 n +1 admits a... -
Generalized derivations with nilpotent values in semiprime rings
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Cheng-Kai Liu --- National Changhua University of Education, TaiwanLet R be a (semi-) prime ring with extended centroid C, let f(X 1, … , Xk ) be a multilinear polynomial over C in k noncommutative indeterminates which is not central-valued on R and let g be a generalized derivation of... -
Sophie Germain prime p and the permutation of product of first p cycles
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: M. Makeshwari --- Central University of Tamil Nadu, India V.P. Ramesh --- Central University of Tamil Nadu, India R. Thangadurai --- Harish-Chandra Research Institute, A CI of Homi Bhabha National Institute, IndiaFor a natural number n, the permutation (n!) is defined as the left-to-right product of the first n cycles, namely, . In this article, we prove that for any natural number n, 2 is a primitive root of 2n +... -
Index characterization and monogenity of septic number fields defined by x 7 + ax 4 + b
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Omar Kchit --- Sidi Mohamed ben Abdellah University, MoroccoIn this paper, we calculate the index of any septic number field K generated by a root α of a monic irreducible trinomial F(x) = x 7 + ax 4 + b ∈ ℤ[x]. Our approach is based on Engstrom’s... -
On z-ideals and z-closure operations of semirings, I
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Amartya Goswami --- University of Johannesburg, South AfricaThe aim of this series of papers is to study z-ideals of semirings. In this article, we introduce some distinguished classes of z-ideals of semirings, which include z-prime, z-semiprime, z-irreducible, and z-strongly irreducible ideals and study some of their properties... -
Partially ordered rings with negative squares
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Nhi Durtschi --- University of Houston-Clear Lake, USA Jingjing Ma --- University of Houston-Clear Lake, USA R.H. Redfield --- Hamilton College, USAA partially ordered ring (R, ≤) with negative squares is a partially ordered ring in which for some element a ∈ R, a 2 < 0. In this paper, we study this class of partially ordered rings. It is shown... -
Further remarks on z-ideals of semirings
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Amartya Goswami --- University of Johannesburg, South Africa Ahmed Maatallah --- University of Monastir, Faculty of Sciences of Monastir, Research Laboratory on Algebra, TunisiaIn this note, we revisit certain results from a previous work of the first author concerning z-ideals of semirings. We demonstrate that the assumption of the semiring being a bzi-semiring can be dispensed with. Additionally, we propose a revised definition... -
Nil Modules and the Envelope of a Submodule
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: David Ssevviiri --- Makerere University, Uganda Annet Kyomuhangi --- Busitema University, UgandaLet R be a commutative unital ring and N be a submodule of an R-module M. We show that: 1) the semiprime radical is an invariant on submodules generated by the ascending chain of envelopes of a given submodule; 2)... -
On SVc -Spaces
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Amir Veisi --- Yasouj University, Iran Zahra Keshtkar --- Yasouj University, IranWe say that a topological space X is an SVc-space if Cc (X) is an SV - ring, that is, is a valuation ring for every prime ideal P of Cc (X). The purpose of this paper is to study... -
An infinite family of number fields arising from quadrinomials with given p-indices
Item type: Journal Article • Journal: Quaestiones Mathematicae • Authors: Omar Kchit --- Sidi Mohamed ben Abdellah University, MoroccoLet be a number field defined by a monic irreducible quadrinomial , where n > m > 1 are positive integers. In this paper, for any prime number p and for some fixed positive integers ip , we provide infinite...