Student Academic Self‐Concept and Perception of Classroom Environment in Single‐Sex and Coeducational Middle Grades Mathematics Classes

In this article, we present findings from a study that investigated the relationship between all‐girls classes, all‐boys classes, and coeducational classes on student mathematics self‐concept and student perception of classroom environment. Further, we compared responses of girls in all‐girls classes to girls in coeducational classes and responses of boys in all‐boys classes to boys in coeducational classes. Using the Mathematics Attitude Scale and the What Is Happening in This Class? questionnaire, we found no significant differences in student responses on any of the subscales or domains for any of the subgroups, except for Math as a Male Domain. Our findings indicate that student mathematics self‐concept and student perception of the classroom environment are similar regardless of whether students are in a single‐sex or a coeducational class.     

When are definable classes tilting and cotilting classes?

It is known that tilting classes are of finite type, while cotilting classes are not always of cofinite type. We investigate this phenomenon. By using a bijection between definable classes of left modules and definable classes of right modules, we prove that it reflects the asymmetry existing between the notions of covers and envelopes or, otherwise stated, right and left approximations.In particular we show that there exist definable torsion classes containing the injective modules which are not tilting classes.     

Classes on the moduli space of Riemann surfaces through a noncommutative Batalin–Vilkovisky formalism

Using the machinery of the Batalin–Vilkovisky formalism, we construct cohomology classes on compactifications of the moduli space of Riemann surfaces from the data of a contractible differential graded Frobenius algebra. We describe how evaluating these cohomology classes upon a well-known construction producing homology classes in the moduli space can be expressed in terms of the Feynman diagram expansion of some functional integral. By computing these integrals for specific examples, we are able to demonstrate that this construction produces families of nontrivial classes.     

Hamming weight enumerators of multi-twisted codes with at most two non-zero constituents

In this paper, we explicitly determine Hamming weight enumerators of several classes of multi-twisted codes over finite fields with at most two non-zero constituents, where each non-zero constituent has dimension 1. Among these classes of multi-twisted codes, we further identify two classes of optimal equidistant linear codes that have nice connections with the theory of combinatorial designs and several other classes of minimal linear codes that are useful in constructing secret sharing schemes with nice access structures. We also illustrate our results with some examples.     

一种广义周期Besov类的多元周期多项式样条逼近

本文证明多元多项式周期样条空间是某些多元周期光滑函数类的关于Kolmogorov n-宽度的弱渐近极子空间．给出了广义周期Besov类的一种推广，得到了空间元素的一种表示定理，不仅给出了一种多元周期多项式样条算子．而且证明了所得的结果．     

Tautological Classes of the Stack of Rational Nodal Curves

This is the second in a series of three papers in which we investigate the rational Chow ring of the stack 𝔐₀ consisting of nodal curves of genus 0. Here we define the basic classes: the classes of strata and the Mumford classes.     

Some applications of Miller-Mocanu lemma on certain classes of meromorphic functions

In this paper, making use of a linear operator we introduce and study certain new classes of meromorphic functions. We derive some inclusion results. These classes contain many known classes as a special case.     

Certain Classes of Analytic Functions Related to the Crescent-Shaped Regions

In this paper, we study certain classes of analytic functions which satisfy a subordination condition and are associated with the crescent-shaped regions. We first give certain integral representations for the functions belonging to these classes and also present a relevant example. Making use of some known lemmas, we derive sufficient conditions for the functions to be in these classes. Some results on coefficient estimates are also obtained.     

Analysis of a finite buffer model with two servers and two nonpreemptive priority classes

In this paper, we analyze a finite buffer queueing model with two servers and two nonpreemptive priority service classes. The arrival streams are independent Poisson processes, and the service times of the two classes are exponentially distributed with different means. One of the two servers is reserved exclusively for one class with high priority and the other server serves the two classes according to a nonpreemptive priority service schedule. For the model, we describe its dynamic behavior by a four-dimensional continuous-time Markov process. Applying recursive approaches we present the explicit representation for the steady-state distribution of this Markov process. Then, we calculate the Laplace–Stieltjes Transform and the steady-state distribution of the actual waiting times of two classes of customers. We also give some numerical comparison results with other queueing models.     

关于局部次指数分布的一个注记

通过次指数密度函数建立了局部次指数分布类的一个等价刻画.作为其应用,我们证明了局部次指数分布类不具有卷积封闭性.     

Extendable cohomologies for complex analytic varieties

We introduce a cohomology, called extendable cohomology, for abstract complex singular varieties based on suitable differential forms. Beside a study of the general properties of such a cohomology, we show that, given a complex vector bundle, one can compute its topological Chern classes using the extendable Chern classes, defined via a Chern–Weil type theory. We also prove that the localizations of the extendable Chern classes represent the localizations of the respective topological Chern classes, thus obtaining an abstract residue theorem for compact singular complex analytic varieties. As an application of our theory, we prove a Camacho–Sad type index theorem for holomorphic foliations of singular complex varieties.     

幺半群的内射类及投射类刻画

类比于一般环上模的内射类,定义了幺半群上的S-系的内射类和投射类,并利用它们刻画了几类特殊的幺半群．证明了完全内射幺半群和完全拟内射幺半群是等价的．并且证明了对于标致幺半群S,它是完全投射的当且仅当它是完全拟投射的当且仅当它上面的投射S-系构成了一个投射类．     

二元复合Poisson风险模型的几个结果

本文研究具有相依关系的一类风险模型.得到了由不同类别的索赔产生的破产时赤字分布的渐近结果以及指数索赔下的精确结果.同时研究了带伽玛过程干扰的古典风险过程.     

On Subspaces of Bloch Space and Series with Hadamard Gaps

本文研究了由修改的Ｂｅｓｏｖ模和Ｃａｒｌｅｓｏｎ测度所定义的Ｂｌｏｃｈ空间的一类子空间．利用这类子空间与Ｈａｄａｍａｒｄ缺项级数之间的关系，证明了他们之间的包含关系．作为所得结果的一个简单推论，本文对Ｋ．Ｓｔｒｏｅｔｈｏｆ关于ＢＭＯＡ和ＶＭＯＡ的一个未解决的问题作出了否定的回答．     

Optimal server scheduling in nonpreemptive finite-population queueing systems

We consider a finite-population queueing system with heterogeneous classes of customers and a single server. For the case of nonpreemptive service, we fully characterize the structure of the server's optimal service policy that minimizes the total average customer waiting costs. We show that the optimal service policy may never serve some classes of customers. For those classes that are served, we show that the optimal service policy is a simple static priority policy. We also derive sufficient conditions that determine the optimal priority sequence.     

非幂零极大子群共轭类类数给定的有限群

证明了非幂零极大子群共轭类类数等于2的有限群必可解,并给出了非幂零极大子群同阶类类数等于2的非可解群的等价刻画.     

关于强J-空间与JHB-空间

引入了两个很有联系的空间类JHB-空间与强J HB-空间，分别推广了J-空间与强J-空间.讨论了J-空间、强J-空间、J HB-空间及强JHB-空间类间的相包含关系及此四空间类逆包含的条件，还得到了JHB-空间的内部刻画，并证明了若对每个α∈S，Xα.都是非紧的连通空间，则积空间∏α∈S Xα是强J-空间。     

Generalized Affine Functions and Generalized Differentials

We study some classes of generalized affine functions, using a generalized differential. We study some properties and characterizations of these classes and we devise some characterizations of solution sets of optimization problems involving such functions or functions of related classes.