两个矩阵乘积{1,3}-逆和{1,4}-逆反序律的一个充要条件

本文我们给出了B{1,3}A{1,3}(AB){1,3}和B{1,4}A{1,4}(AB){1,4}的一个等价性条件,并由此得到了(AB)+=B+A+的一个新的充分必要条件.     

关于A{1,3}、A{1,4}广义逆矩阵的一些性质

对A{1,3}、A{1,4}这两类广义逆矩阵进一步讨论,得到了它们的若干代数性质,同时给出了它们在最小二乘法解和极小问题解中的应用。     

一种矩阵广义逆的求法

本文运用矩阵的酉相抵标准形定理,推导出{1}—广义逆,{1.4}—广义逆,{1,3}—广义逆,{1,2,3.4}—广义逆的新形式.在理论证明上非常有用。     

广义逆的递推算法及其对最优状态估计的应用

在简化 {1}、 {1,2}和 {1,2,3,4}逆的计算并给出 {1,3}、 {1,2,3}、 {1,4}和 {1,2,4}逆的算法的基础上,得到了递推滤波、固定点平滑、固定滞后平滑与预报算法。且由此得到离散线性随机和定常系统的最优线性最小偏差估计,给出了最优线性无偏估计的充要条件而无需初始状态的先验知识。对定常系统,给出了滤波、固定点平滑、固定滞后平滑和预报形式的无差状态观测器而无需假定系统是时不变和完全可观测的。     

两个矩阵乘积的{1，2，3M}-逆反序律的刻划

矩阵乘积的加权广义逆在理论研究与数值计算等方面有许多重要应用而引起人们的关注．文章利用广义Schur补的极大（小）秩的表示式,获得了二矩阵乘积的{1,2,3M}-逆反序律成立的一个新刻划,从而丰富与完善了加权广义逆反序律的相关结果。     

格值矩阵的逆及广义逆

探讨了基于格半群上的矩阵的逆和广义逆等问题,给出了格值矩阵的逆、{1}-广义逆和M—P广义逆的概念和它们存在的条件,以及格值矩阵A的任意一个{1}-广义逆的具体形式、M—P广义逆的存在性和唯一性．     

对|1|-逆矩阵的计算方法探讨

矩阵的{1}-逆不只一个,而且计算比较困难。本文旨在给出计算{1}-逆矩阵的一种方法。这种方法,很容易通过计算机编程来达到求{1}-逆矩阵的目的。     

高三数学回扣课本复习指南

一 集合、函数、不等式、导数 （一）选择题 1．设A={x｜｜x-3｜≤4}，B={y｜y=√x-2＋√2-x}，则A∩B为（ ）． A．{0} B．{2} C．φ D．{x｜2≤x≤7}[编者按]     

促进数学思维训练的好题

一、选择题 1．已知全集U=R,集合A＝{x｜x^2-2x-3〉O｝,B={x｜2〈x〈4｝,那么集合（GuA）ΩB=（ ）．A．{x｜-1≤x≤4}B．{x｜2〈z≤3}C．{x｜2≤x〈3}D．{x｜-1〈x〈4}     

忽视式子中参数的影响忽视式子中参数的影响忽视式子中参数的影响

已知数列{an}前n项的和为Sn,Sn=a^n-1（a≠0）,那么数列{an}（ ）． A．一定是等差数列 B．一定是等比数列     

Developmental Relations Among Behavioral Inhibition,Anxiety, and Attention Biases to Threat and Positive Information

This study examined relations between behavioral inhibition (BI) assessed in toddlerhood (n = 268) and attention biases (AB) to threat and positive faces and maternal‐reported anxiety assessed when children were 5‐ and 7‐year‐old. Results revealed that BI predicted anxiety at age 7 in children with AB toward threat, away from positive, or with no bias, at age 7; BI did not predict anxiety for children displaying AB away from threat or toward positive. Five‐year AB did not moderate the link between BI and 7‐year anxiety. No direct association between AB and BI or anxiety was detected; moreover, children did not show stable AB across development. These findings extend our understanding of the developmental links among BI, AB, and anxiety.     

Development of Preterm and Full-Term Infant Ability on AB, Recall Memory, Transparent Barrier Detour, and Means-End Tasks

10 preterm and 10 full-term infants were tested longitudinally from 28 to 60 weeks of age on a modified version of the AB task, a nonreaching AB task, a Barrier Detour task, a Means-End task, and Perseveration in the Means-End task. Results show that age-corrected (age since conception) premature infants tolerated longer delays than full-term infants on the modified and nonreaching AB tasks. However, when compared by chronological age (age since birth), there were no group differences on either the reaching or nonreaching AB task. No group differences were found on Barrier Detour, Means-End, or Perseveration in either the age-corrected or chronological age comparisons. The results suggest that the function that mediates modified AB performance is one of memory and not of perseveration or means-end ability. Further, these findings suggest that current proposals about brain development based on single samples of infants may be tenuous. Finally, the results of this study suggest that development of the brain structure(s) that mediate modified AB performance is strongly influenced by experience in the postnatal environment.     

UNDOING GENDER THROUGH LEGISLATION AND SCHOOLING: THE CASE OF AB 537 AND AB 394 IN CALIFORNIA, USA

This article investigates California laws AB 537: The Student Safety and Violence Prevention Act of 2000, and the recently enacted AB 394: Safe Place to Learn Act. Both demand that gender identity and sexual orientation be added to the lexicon of anti-harassment protection in public education. However, despite these progressive measures, schools have an unconscious acceptance of heteronormativity and gendered norms, which undermines both the spirit and language of these laws. This paper examines how California schools can both change standard practices and realise the transformative social change that laws like AB 537 and AB 394 can instigate. I assert that the systemic implementation of these laws, through the adoption, enforcement and evaluation of existing AB 537 Task Force Recommendations, is necessary for their success. My second assertion is that AB 537 and AB 394 have the potential to change and reconstitute gender-based and heteronormative standards at school sites.     

谓词性并列短语否定表达的模式选择

在现代汉语中,谓词性并列短语的否定表达常采用NegANegB（“AB”表示由并列项A、B组成的谓词性并列短语）模式。当Neg重读或添加其他成分,或者当“AB”接近典型的自然并列短语时,才能采用NegAB模式,从而保证Neg能够对谓词性并列短语AB进行整体否定。     

关于矩阵的迹的不等式

指出了关于正定矩阵的迹中几个主要结论的错误并加以修正，得到了关于可正对角化矩阵的迹的等式tr（AB）^n=[tr（AB）]^n=tr（A^nB^n）成立的条件．     

Development of the ability to use recall to guide action, as indicated by infants' performance on AB

25 infants were tested every 2 weeks on the AB Object Permanence Task devised by Piaget, from the age when they first reached for a hidden object until they were 12 months. The delay between hiding and retrieval necessary to produce the AB error increased continuously throughout this period at an average rate of 2 sec/month, from under 2 sec at 7 1/2 months to over 10 sec by 12 months. All children displayed the AB error repeatedly over the months of testing. Large between-children differences in delay needed for the AB error were found at each age. Girls tolerated longer delays than boys. The characteristic pattern to the AB error did not vary over age or sex. Range of delay producing the AB error in any child was small. Errors disappeared when delays were reduced by 2-3 sec, and reaching became random or severely perseverative when delays were increased 2-3 sec above the level producing AB error. AB provides an index of the ability to carry out an intention based on stored information despite a conflicting habitual tendency.     

名词性概念汉英词汇表征差异的对比研究

本文以对从三本词典及过往相关研究中收集的约1655个语料进行的分析为基础,较为系统全面地探讨名词性概念在汉英词汇表征上存在的差异。研究发现,汉英在名词性概念词汇表征上的差异主要分为两大类:内在差异和外在差异。其又可进一步分为7小类,用大写字母A、B、C和D分别表示为AB/BA,AC/BC,AB/CD,AB/B,A/AB,A'B'/C'D'和A*B*/C*D*。     

A comparison of the Rescorla-Wagner and Pearce models in a negative patterning and a summation problem

In two experiments, we examined two related conditioning problems previously investigated by Red-head and Pearce (1995a) and Pearce, Aydin, and Redhead (1997). Experiment 1 involved an A+, B+, C+, AB+, AC+, BC+, ABC2 discrimination. The Rescorla-Wagner model predicts that response to AB, AC, and BC will be greater than that to A, B, and C at asymptote, whereas the Pearce model makes the opposite prediction. In Experiment 2, we investigated the responding to a novel ABC compound in groups trained with either A+, B+, C+ or AB+, AC+, BC+. The Rescorla-Wagner model predicts greater response to ABC in the group trained with A+, B+, C+ than in the group trained with AB+, AC+, BC+, whereas the Pearce model makes the opposite prediction. In contrast to the findings of Redhead and Pearce (1995a) and Pearce et al. (1997) in pigeon autoshaping, our findings in rabbit eyelid conditioning support the Rescorla-Wagner model.     

祁阳方言中"AB"式形容词

祁阳方言中“AB”式状态形容词非常丰富，这类形容词的重叠式也非常多样，其中最有特色的是它的重叠形式AABB式。祁阳方言中“AB”式形容词能够大量进行AABB式重叠，普通话中“AB”式形容词是不能这样重叠的。