函子范畴的等价

本文建立了函子范畴等价的Ｍｏｒｉｔａ理论．考虑的主要问题是ｍｏｄＣ何时等价于ｍｏｄＣ′及这些等价条件．同时定义了函子范畴的双模和函子张量积，并刻画了等价函子．     

半模的张量积

本文引入了半模的张量积的泛性定义，给出了半模范畴中的有向正向系的上极限以及任意一个半模同态的上核，讨论了半模张量积的若干性质，主要结果是：证明了张量函子保持半模的右正合性和上积，并且上积保持半模的平坦性，半模范畴中的张量函子保持上极限和上核．     

定义在范畴_RM_n~l上的张量函数

文[1]引进了左R-n模范畴_RM_n~1,将Hom函子推扩到_RM_n~l上,且讨论了它的拟正合性。在模范畴中,张量函子与Hom函子一样是一个重要的函子。文[2]企图在_RM_n~l上建立相应的张量积,并证明张量函子M_n~:AG_(rn)→_RM_n~l与Hom函子Hom(M_):AG_(rn)′→_RM_n~l为伴随对。但其构造的交换自由n-群仅对满足(E)条件的交换n-群具有泛性,故其张量积亦只是     

R-n模张量积与张量函子

文[1]引进了左R-n模范畴_RM_n~L,本文是在_RM_n中,建立相应的张量积,证明了它的存在性与唯一性,并讨论了张量函子与Hom函子的伴随性。 文中沿用[1]的记号。     

$D_4$型李代数包络代数旋模的范畴化

本文我们定义复数域$C$上一般线性李代数${\rm gl}_n$ BGG 范畴的若干子范畴及其上的投射函子,利用这些子范畴和投射函子范畴化了$D_4$型李代数包络代数旋模的$n$-次张量积.     

纯正半群的张量积的局部化

本文在半群范畴中证明了两个纯正半群Ａ和Ｂ的张量积在某一个子半群上的局部化是ＡＢ的最大群同态象，同时还证明了张量积的局部化同构于局部化的张量积     

格序模的f—复盖

J.Martinez首先利用同调的方法研究了格序结构,讨论了偏序模的张量积.W.Powell和A.Bigard分别在1981年和1973年研究了格序模的自由对象,描述了自由f—模的结构.作者推广并且改进了他们的工作,讨论了格序模的f—张量积.本文讨论格序模的f—模复盖,给出复盖函子,f—张量积函子和嵌入函子的关系.     

某些半群子范畴中的张量积

半群范畴S中张量积首先在中引入。T∈ob S称为A,B∈ob S的张量积(记为AB),如果存在双同态t:A×B→T(相当于中线性平衡映射),且对于任意双同态s:A×B→C∈ob S总存在唯一的同态μ:T→C,使s-ut。确认了张量积的存在唯一。等引入交换半群、半格等子范畴中的张量积,其定义与上述基本相同,仅将S改为该子范畴,此外该划了一些半群类的张量积。本文在§1从任意半群簇V中张量积与其在S中     

自由函子及其伴随函子

本文证明了由集合范畴到f-模范畴的自由函子的存在性，构造了自由函子的伴随函子。     

L-fuzzy模范畴中张量函子的正合性

研究了L-fuzzy模范畴中张量函子的正合性,给出平坦L-fuzzy模的概念,讨论了张量函子的正合性与L-fuzzy模的平坦性之间的关系。     

Tensor calculus: unlearning vector calculus

Tensor calculus is critical in the study of the vector calculus of the surface of a body. Indeed, tensor calculus is a natural step-up for vector calculus. This paper presents some pitfalls of a traditional course in vector calculus in transitioning to tensor calculus. We show how a deeper emphasis on traditional topics such as the Jacobian can serve as a bridge for vector calculus into tensor calculus.     

Tensor products of subnormal operators

We shall use a -algebra approach to study operators of the form where is subnormal and is normal. We shall determine the spectral properties for these operators, and find the minimal normal extension and the dual operator. We also give a necessary condition for to contain a compact operator and a sufficient condition for the algebraic equivalence of and .

We also consider the existence of a homomorphism satisfying . We shall characterize the operators such that exists for every operator .

The problem of when is unitarily equivalent to is considered. Complete results are given when and are positive operators with finite multiplicity functions and has compact self-commutator. Some examples are also given.

     

Derivations of Tensor Product Algebras

It is known that under certain finite dimensionality condition the derivation algebra of tensor product of two algebras can be obtained in terms of the derivation algebras and the centroids of the involved algebras. We extend this theorem to infinite dimensional case and as an application, we determine the derivation algebra of the fixed point algebra of the tensor product of two algebras, with respect to the tensor product of two finite order automorphisms. These provide the framework for calculating the derivations of some infinite dimensional Lie algebras.     

Reductions of Tensor Categories Modulo Primes

We study good (i.e., semisimple) reductions of semisimple rigid tensor categories modulo primes. A prime p is called good for a semisimple rigid tensor category 𝒞 if such a reduction exists (otherwise, it is called bad). It is clear that a good prime must be relatively prime to the Müger squared norm |V|² of any simple object V of 𝒞. We show, using the Ito–Michler theorem in finite group theory, that for group-theoretical fusion categories, the converse is true. While the converse is false for general fusion categories, we obtain results about good and bad primes for many known fusion categories (e.g., for Verlinde categories). We also state some questions and conjectures regarding good and bad primes.     

Tensor categories attached to double groupoids

The construction of a quantum groupoid out of a double groupoid satisfying a filling condition and a perturbation datum is given. Several important classes of examples of tensor categories are shown to fit into this construction. Certain invariants such as a pivotal group-like element and quantum and Frobenius–Perron dimensions of simple objects are computed.     

Tensor Tomography: Progress and Challenges

The authors survey recent progress in the problem of recovering a tensor field from its integrals along geodesics. Several open problems are also proposed.     

求解具有张量积结构线性系统的共轭梯度法

本文考虑具有张量积结构线性系统的数值解法．该线性系统常常来源于高维立方体上线性偏微分方程的有限差分离散化．利用张量一矩阵乘法,给出了基于张量格式的求解这类线性系统的共轭梯度法．与求解标准线性系统的共轭梯度法比较,新的算法能够节约大量的计算量及存储空间．