C_n-内射模及其刻画

设R是任何环,n是非负整数,L是R-模.若对任何n-余挠模C,有Ext_R~1(C,L)=0,则L称为C_n-内射模.R是Artin半单环当且仅当每个R-模是C_n-内射模,R是弱整体维数不超过n的环当且仅当每个n-余挠模是C_n-内射模.最后引入C_nI-遗传环,即C_n-内射模的商模还是C_n-内射模的环,并且R是C_nI-遗传环当且仅当R上每个n-余挠模的投射维数不超过1.     

φ-平坦余挠理论

引进并研究φ-平坦余挠理论,证明了该余挠理论是完全余挠理论.设R是φ-环,则φ-平坦余挠理论与经典平坦余挠理论相等当且仅当R是整环.作为应用,给出了非诣零凝聚环和φ-VN正则环的新刻画和φ-平坦模的包类性质;证明了每个R-模都有一个满的φ-平坦包当且仅当R是非诣零凝聚环,并且φ-平坦模关于子模封闭.     

关于n-余挠模

设 R 为环,M 为右 R 模,n是一个给定的非负整数.若对任意平坦右R模 N 都有Ext n 1 R (N, M) = 0则称M 为 n-余挠模.若对任意n-余挠右R-模 N都有 Ext1R(M, N) = 0则称M为n-平坦模.本文给出了n-余挠模与n-平坦模的一些性质.     

Gorenstein n-余挠模及Gorenstein n-余挠维数

在右n-凝聚环上研究Gorenstein n-余挠模的相关性质,证明了在右n-凝聚环上Gorenstein n-平坦模的Gorenstein n-余挠包络是Gorenstein n-平坦模,Gorenstein n-余挠模的Gorenstein n-平坦覆盖是Gorenstein n-余挠模;将n-余挠模的相关性质推广到Gorenstein n-余挠模上;在右n-凝聚环上讨论模和环的Gorenstein n-余挠维数的相关性质,给出了右n-凝聚环的左Gorenstein n-余挠整体维数与其他同调维数之间的一些等价刻画.     

C_n-平坦模的一些结果

本文引入并研究了C_n-平坦模。设R是任何环,n是非负整数,称右R-模M是C_n-平坦模,类指对任何n-余挠左R-模C,都有Tor■(M,C)=0。本文证明了M是平坦模当且仅当M是C_n-平坦模且fd_RM≤1,C_n-平坦模对纯子模以及其对应的纯商模封闭;还证明了C-平坦模与C_1-平坦模就是平坦模,并且当R是整环时,无挠的C_2-平坦模也是平坦模;R的弱整体维数不超过n当且仅当任意右R-模的第n次合冲是C_n-平坦模;R是von Neumann正则环当且仅当每个右R-模是C_n-平坦模。     

n-余表现维数与环扩张

利用n-余表现模定义了模舾的n-余表现雏数COPnd（M）,刻画了右n-余凝聚环,即R为右n-余凝聚环当且仅当对于任意右R-模M,均有COPnd（M）=COPn＋1d（M）,并研究了在环扩张下模的n-余表现雏数的若干关系式。     

(d,n)-余挠模与(d,n)-平坦模的环刻画

设R是环,研究了(d,n)-余挠模和(d,n)-平坦模的应用,证明了每一个右R-模是(d,n)-余挠模当且仅当每一个(d,n)-平坦右R-模是(d,n)-余挠模;对偶地,证明了每一个右R-模是(d,n)-平坦模当且仅当每一个循环右R-模是(d,n)-平坦模.最后给出了这两类模在多项式环下的等价刻画.     

关于n-表现维数

利用n-表现模定义了模M与环R的n-表现维数FPnd(M)与FPnD(R),给出了FPnd(M),fd(M)及pd(M)之间的关系,刻画了右n-凝聚环,即R为右n-凝聚环当且仅当对于任意右R-模M,均有FPnd(M)=FPn+1d(M).在右n-凝聚环R上给出了rgD(R),wD(R),FPnD(R)之间的关系.     

强极大内射维数与强极大内射维数有限的模类

引入了模的强极大内射维数和环R的右整体强极大内射维数,并给出了这些维数的一些刻画.设n是非负整数,证明了若R是右广义Noetherian环且SMI-d(R)≤n,则(SMI≤n,(SMI≤n)⊥)是完备的余挠对,其中SMI≤n是强极大内射维数不超过n的模类.最后证明了(SMP,SMI)是余挠对,其中SMP是强极大投射模类,SMI是强极大内射模类.     

n-凝聚环的若干刻划

通过引入FPn-内射右模与FPn-平坦左模来刻划右n-凝聚环，证明了R是右n-凝聚环当且仅当FPn-内射右R-模组成的模类是上分解的(n≥1)，当且仅当FPn-平坦左R-模组成的模类是分解的(n≥2)．     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

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