共查询到19条相似文献,搜索用时 93 毫秒
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首先仿照幂零群的处理方式,引进幂零Lie环的下中心列,并给出Le环的下中心列商群与Lab的张量积的关系,最后根据群上的Hall幂零性准则,给出了Lie环的Hall幂零性准则,并予以证明. 相似文献
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群的代数结构的提升,为一般代数系统的代数结构的提升提供了一种研究方法,于是人们自然会想到环的代数结构的提升问题.1988年,李洪兴教授首次提出了HX环的概念,开始了环代数结构的提升.2000年,钟育彬给出了非平凡HX环的例子,说明了非平凡HX环的存在性.本文建立了一般的HX环与幂环的构造理论,同时还给出一些非平凡HX环与非平凡幂环的例子. 相似文献
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满足A2=A的n阶方阵A称为幂等矩阵,它是矩阵环Mn(F)的一个幂等元;满足r(A)=r(A2)的n阶方阵A称为秩幂等矩阵。它们与空间的分解、不变子空间的研究有密切关系。利用线性空间的理论方法研究幂等矩阵与秩幂等矩阵的性质,分别得到与它们等价的一些充要条件。 相似文献
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王骁力 《南阳师范学院学报》2012,11(12):1-5
首先讨论了文中所需的关于循环环和剩余类环的基本结果,然后借助这些结果对于循环环的子结构、商结构以及特殊元素进行了分析.关于子结构问题,给出了任意循环环的全部子环、理想、极大理想、素理想;关于商结构问题,讨论了商环的结构和商环为域的条件;也讨论了循环环中的单位元素、零因子元素、可逆元素、幂等元素、幂零元素等特殊元素的性质;给出了循环环的自同构群的阶的计算公式. 相似文献
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奚欧根 《宁波大学学报(教育科学版)》1988,(2)
本文定义了Γ-环的局部强幂零理想与拟局部强幂零理想,研究了局部强幂零根与拟局部强幂零根,并且证明了任何Γ-环都有拟局部强幂零根,且拟局部强幂零根等于局部强幂零根。 相似文献
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本文主要利用比较判别法,Sdding公式和Raabe判别法证明了幂级教^∞∑n=0(2n)!/(n!)^2x^2n在其收敛区间右端点的发散性。 相似文献
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设R是一个环,映射f:R→R称为一个幂自同态,如果存在n>1使f:x→xn为R的一个环同态.本文将完全刻划出无零因子环的所有幂自同态. 相似文献
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新媒体时代比较教育研究面临的挑战与选择 总被引:1,自引:0,他引:1
新媒体时代的变革力量带来了比较教育研究队伍的扩大与研究主体性增强;由于文化同质化加剧,相似性增强,导致国别间教育可比性的提高;比较教育研究时空得到拓展与研究方法呈现综合化趋势。比较教育研究面临新媒体时代的挑战,只有寻求变革与发展自觉,才能促进学科的进步与繁荣。为此,在新媒体时代,比较教育研究应坚守教育的民族性,在多元角逐中相融共生;拓展比较教育研究的视野,寻求教育文化的优化;选取适应研究对象的方法,促进比较教育学的发展。 相似文献
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The purpose of this study was to test methods that strengthen the comparability claims about annual determinations of student proficiency in English language arts, math, and science (Grades 3–12) in the New Hampshire Performance Assessment of Competency Education (NH PACE) pilot project. First, we examined the literature in order to define comparability outside the bounds of strict score interchangeability and explored methods for estimating comparability that support a balanced assessment system for state accountability such as the NH PACE pilot. Second, we applied two strategies—consensus scoring and a rank‐ordering method—to estimate comparability in Year 1 of the NH PACE pilot based upon the expert judgment of 85 teachers using 396 student work samples. We found the methods were effective for providing evidence of comparability and also detecting when threats to comparability were present. The evidence did not indicate meaningful differences in district average scoring and therefore did not support adjustments to district‐level cut scores used to create annual determinations. The article concludes with a discussion of the technical challenges and opportunities associated with innovative, balanced assessment systems in an accountability context. 相似文献
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论可比性——比较文学的一个重要理论问题 总被引:5,自引:0,他引:5
陈惇 《北京师范大学学报(社会科学版)》2000,(3)
可比性是关系到作为一门学科的比较文学能不能建立、比较研究能不能有效进行的重要理论问题。文学现象之间实际存在的亲缘关系、价值关系和交叉关系是可比性的客观基础。在中西比较文学研究中 ,为掌握好可比性 ,必须做好发现、考察、抉择这样三个方面的工作 相似文献
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When a computerized adaptive testing (CAT) version of a test co-exists with its paper-and-pencil (P&P) version, it is important for scores from the CAT version to be comparable to scores from its P&P version. The CAT version may require multiple item pools for test security reasons, and CAT scores based on alternate pools also need to be comparable to each other. In this paper, we review research literature on CAT comparability issues and synthesize issues specific to these two settings. A framework of criteria for evaluating comparability was developed that contains the following three categories of criteria: validity criterion, psychometric property/reliability criterion, and statistical assumption/test administration condition criterion. Methods for evaluating comparability under these criteria as well as various algorithms for improving comparability are described and discussed. Focusing on the psychometric property/reliability criterion, an example using an item pool of ACT Assessment Mathematics items is provided to demonstrate a process for developing comparable CAT versions and for evaluating comparability. This example illustrates how simulations can be used to improve comparability at the early stages of the development of a CAT. The effects of different specifications of practical constraints, such as content balancing and item exposure rate control, and the effects of using alternate item pools are examined. One interesting finding from this study is that a large part of incomparability may be due to the change from number-correct score-based scoring to IRT ability estimation-based scoring. In addition, changes in components of a CAT, such as exposure rate control, content balancing, test length, and item pool size were found to result in different levels of comparability in test scores. 相似文献
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主要讨论abel环的一些扩张性质,以及它与Armendariz环,reduced环,Boole环和semicommutative环之间的关系. 相似文献
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林大华 《贵州教育学院学报》2011,(3):1-4
特征是环的一个重要特性,对环的结构起着重要的作用。通过对环的特征的初步综述,得到了环的特征的若干性质及等价条件,并进一步用特征刻画了环的结构。 相似文献
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人类文化存在着同质和异质,文学作为文化的象征和集中表现,也必然有相同和异同的因素,这就使具有跨越性的文学现象之间具有了可比性。可比性是一种内在的价值,当我们把问题提到一定范围之内,在一个特定的标准下,透视相关的文学现象时,可比性就会显现出来。 相似文献