arXiv subjects

Pu Zhang

Publications and source records attributed to Pu Zhang.

At least 91 records · Page 5Linked to original sources

arXiv2017

Characterization of Lipschitz spaces via commutators of the Hardy-Littlewood maximal function

Let $M$ be the Hardy-Littlewood maximal function and $b$ be a locally integrable function. Denote by $M_b$ and $[b,M]$ the maximal commutator and the (nonlinear) commutator of $M$ with $b$. In this paper, the author consider the boundedness of $M_b$ and $[b,M]$ on Lebesgue spaces and Morrey spaces when $b$ belongs to the Lipschitz space, by which some new characterizations of the Lipschitz spaces are given.

math.CA↗

arXiv2016

Commutators of multilinear Calderón-Zygmund operators with kernels of Dini's type and applications

Let $T$ be a multilinear Calderón-Zygmund operator of type $ω$ with $ω(t)$ being nondecreasing and satisfying a kind of Dini's type condition. Let $T_{Π\vec{b}}$ be the iterated commutators of $T$ with $BMO$ functions. The weighted strong and weak $L(\log{L})$-type endpoint estimates for $T_{Π\vec{b}}$ with multiple weights are established. Some boundedness properties on weighted variable exponent Lebesgue spaces are also obtained. As applications, multiple weighted estimates for iterated commutators of paraproducts and bilinear pseudo-differential operators with mild regularity are given.

math.CA↗

arXiv2016

Unbounded ladders induced by Gorenstein algebras

The derived category $D({\rm Mod}A)$ of a Gorenstein triangular matrix algebra $A$ admits an unbounded ladder; and this ladder restricts to $D^-({\rm Mod})$ {\rm(}resp. $D^b({\rm Mod})$, $D^b({\rm mod})$, $K^b({\rm proj})${\rm)}. A left recollement of triangulated categories with Serre functors sits in a ladder of period $1$; as an application, the singularity category of $A$ admits a ladder of period $1$.

math.RT↗

arXiv2016

Unbounded ladders induced by Gorenstein algebras

The derived category of a Gorenstein triangular matrix algebra $A$ admits an unbounded ladder, which is of period $3$ if $A = T_2(B)$. Also, a left recollement of triangulated categories with Serre functors sits in a ladder of period $1$; as an application, the singularity category of $A$ admits a ladder of period $1$.

math.RT↗

arXiv2016

Monic monomial representations I Gorenstein-projective modules

For a $k$-algebra $A$, a quiver $Q$, and an ideal $I$ of $kQ$ generated by monomial relations, let $Λ: = A\otimes_k kQ/I$. We introduce the monic representations of $(Q, I)$ over $A$. We give properties of the structural maps of monic representations, and prove that the category ${\rm mon}(Q, I, A)$ of the monic representations of $(Q, I)$ over $A$ is a resolving subcategory of ${\rm rep}(Q, I, A)$. We introduce the condition ${\rm(G)}$. The main result claims that a $\m$-module is Gorenstein-projective if and only if it is a monic module satisfying ${\rm(G)}$. As consequences, the monic $\m$-modules are exactly the projective $\m$-modules if and only if $A$ is semisimple; and they are exactly the Gorenstein-projective $\m$-modules if and only if $A$ is selfinjective, and if and only if ${\rm mon}(Q, I, A)$ is Frobenius.

math.RT↗

arXiv2016

Categorical resolutions of a class of derived categories

Using the relative derived categories, we prove that if an Artin algebra $A$ has a module $T$ with ${\rm inj.dim}T<\infty$ such that $^\perp T$ is finite, then the bounded derived category $D^b({\rm mod}A)$ admits a categorical resolution; and that for CM-finite Gorenstein algebra, such a categorical resolution is weakly crepant.

math.RT↗

arXiv2015

Point Group Symmetry and Deformation Induced Symmetry Breaking of Superlattice Materials

The point group symmetry of materials is closely related to their physical properties and quite important for material modeling. However, superlattice materials have more complex symmetry conditions than crystals due to their multilevel structural feature. Thus, a theoretical framework is proposed to characterize and determine the point group symmetry of nonmagnetic superlattice materials systematically. A variety of examples are presented to show the symmetry features of superlattice materials in different dimensions and scales. In addition, the deformation induced symmetry breaking phenomenon is also studied for superlattice materials, which has potential application in tuning physical properties by imposing a strain field.

cond-mat.mtrl-sci↗

arXiv2015

Biomimetic Staggered Composites with Highly Enhanced Energy Dissipation: Design, Modeling, and Test

We investigate the damping enhancement in a class of biomimetic staggered composites via a combination of design, modeling, and experiment. In total, three kinds of staggered composites are designed by mimicking the structure of bone and nacre. These composite designs are realized by 3D printing a rigid plastic and a viscous elastomer simultaneously. Greatly-enhanced energy dissipation in the designed composites is observed from both the experimental results and theoretical prediction. The designed polymer composites have loss modulus up to ~500 MPa, higher than most of the existing polymers. In addition, their specific loss modulus (up to 0.43 $Km^2/s^2$) is among the highest of damping materials. The damping enhancement is attributed to the large shear deformation of the viscous soft matrix and the large strengthening effect from the rigid inclusion phase.

cond-mat.mtrl-sci↗

arXiv2014

Ab-initio nanoplasmonics: The impact of atomic structure

We present an ab-initio study of the hybridization of localized surface plasmons in a metal nanoparticle dimer. The atomic structure, which is often neglected in theoretical studies of quantum nanoplasmonics, has a strong impact on the optical absorption properties when sub-nanometric gaps between the nanoparticles are considered. We demonstrate that this influences the hybridization of optical resonances of the dimer, and leads to significantly smaller electric field enhancements as compared to the standard jellium model. In addition we show that the corrugation of the metal surface at a microscopic scale becomes as important as other well-known quantum corrections to the plasmonic response, implying that the atomic structure has to be taken into account to obtain quantitative predictions for realistic nanoplasmonic devices.

physics.optics↗

arXiv2014

Categorical resolutions of a class of derived categories

By using the relative derived categories, we prove that if an Artin algebra $A$ has a module $T$ with ${\rm inj.dim}T<\infty$ such that $^\perp T$ is finite, then the bounded derived category $D^b(A\mbox{-}{\rm mod})$ admits a categorical resolution in the sense of [Kuz], and a categorical desingularization in the sense of [BO]. For CM-finite Gorenstein algebra, such a categorical resolution is weakly crepant. The similar results hold also for $D^b(A\mbox{-}{\rm Mod})$.

math.RT↗

arXiv2014

Objective triangle functors

An (additive) functor F from an additive category A to an additive category B is said to be objective, provided any morphism f in A with F(f) = 0 factors through an object K with F(K) = 0. In this paper we concentrate on triangle functors between triangulated categories. The first aim of this paper is to characterize objective triangle functors F in several ways. Second, we are interested in the corresponding Verdier quotient functors V_F, in particular we want do know under what conditions V_F is full. The third question to be considered concerns the possibility to factorize a given triangle functor F = F_2F_1 with F_1 a full and dense triangle functor and F_2 a faithful triangle functor. It turns our that the behaviour of splitting monomorphisms (and splitting epimorphisms) plays a decisive role.

math.RT↗

arXiv2014

From CM-finite to CM-free

The aim of this paper is twofold. On one hand, we prove a slight generalization of the stability for Gorenstein categories in [SWSW] and [Huang]; and show that the relative Auslander algebra of a CM-finite algebra is CM-free. On the other hand, we describe the bounded derived category, and the Gorenstein defect category introduced in [BJO], via Gorenstein-projective objects; and we show that the Gorenstein defect category of a CM-finite algebra is triangle-equivalent to the singularity category of its relative Auslander algebra.

math.RT↗

arXiv2014

From submodule categories to preprojective algebras

Let S(n) be the category of invariant subspaces of nilpotent operators with nilpotency index at most n. Such submodule categories have been studied already in 1936 by Birkhoff, they have attracted a lot of attention in recent years, for example in connection with some weighted projective lines (Kussin, Lenzing, Meltzer). On the other hand, we consider the preprojective algebra of type A_n; the preprojective algebras were introduced by Gelfand and Ponomarev, they are now of great interest, for example they form an important tool to study quantum groups (Lusztig) or cluster algebras (Geiss, Leclerc, Schroeer). Direct connections between the submodule category S(n) and the module category of the preprojective algebra of type A_{n-1} have been established quite a long time ago by Auslander and Reiten, and recently also by Li and Zhang, but apparently this remained unnoticed. The aim of this note is to provide details on this relationship. As a byproduct we see that here we deal with ideals I in triangulated categories T such that I is generated by an idempotent and T/I is abelian.

math.RT↗

arXiv2013

Representations of quivers over the algebra of dual numbers

The representations of a quiver Q over a field k have been studied for a long time. It seems to be worthwhile to consider also representations of Q over arbitrary finite-dimensional k-algebras A. Here we draw the attention to the case when A = k[ε] is the algebra of dual numbers, thus to the Λ-modules with Λ= kQ[ε]. The algebra Λ is a 1-Gorenstein algebra, therefore the torsionless Λ-modules are known to be of special interest (as the Gorenstein-projective or maximal Cohen-Macaulay modules). They form a Frobenius category \Cal L, thus the corresponding stable category is a triangulated category. As we show, the category \Cal L is the category of perfect differential kQ-modules and the stable category of \Cal L is triangle equivalent to the orbit category of the derived category D^b(mod kQ) modulo the shift. The homology functor H from mod Λ to \mod kQ yields a bijection between the indecomposables in the stable category of \Cal L and those in mod kQ. Our main interest lies in the inverse, it is given by the minimal \Cal L-approximation. Also, we determine the kernel of the restriction of the functor H to \Cal L and we describe the Auslander-Reiten quiver of \Cal L.

math.RT↗

arXiv2013

Monomorphism operator and perpendicular operator

For a quiver $Q$, a $k$-algebra $A$, and a full subcategory $\mathcal X$ of $A$-mod, the monomorphism category ${\rm Mon}(Q, \mathcal X)$ is introduced. The main result says that if $T$ is an $A$-module such that there is an exact sequence $0\rightarrow T_m\rightarrow...\rightarrow T_0\rightarrow D(A_A)\rightarrow 0$ with each $T_i\in {\rm add} (T)$, then ${\rm Mon}(Q, \ ^\perp T) = \ ^\perp (kQ\otimes_k T)$; and if $T$ is cotilting, then $kQ\otimes_k T$ is a unique cotilting $\m$-module, up to multiplicities of indecomposable direct summands, such that ${\rm Mon}(Q, \ ^\perp T)= \ ^\perp (kQ \otimes_k T)$. As applications, the category of the Gorenstein-projective $(kQ\otimes_kA)$-modules is characterized as ${\rm Mon}(Q, \mathcal{GP}(A))$ if $A$ is Gorenstein; the contravariantly finiteness of ${\rm Mon}(Q, \mathcal X)$ can be described; and a sufficient and necessary condition for ${\rm Mon}(Q, A)$ being of finite type is given.

math.RT↗

arXiv2012

Decomposition of torsion pairs on module categories

In this article, we generalize the concept of torsion pairs and study its structure. As a trial of obtaining all torsion pairs, we decompose torsion pairs by projective modules and injective modules. Then we calculate torsion pairs on the algebra KAn and tub categories. At last we try to find all torsion pairs on the module categories of finite dimensional hereditary algebras.

math.RT↗

arXiv2011

Monic representations and Gorenstein-projective modules

Let $Λ$ be the path algebra of a finite quiver $Q$ over a finite-dimensional algebra $A$. Then $Λ$-modules are identified with representations of $Q$ over $A$. This yields the notion of monic representations of $Q$ over $A$. If $Q$ is acyclic, then the Gorenstein-projective $\m$-modules can be explicitly determined via the monic representations. As an application, $A$ is self-injective if and only if the Gorenstein-projective $\m$-modules are exactly the monic representations of $Q$ over $A$.

math.RT↗

arXiv2011

Generalized $d$-Koszul modules

Generalized \dK modules are introduced to solve an open problem: the odd Ext-module $\Eod(M)$ of a \dK module $M$ over a $d$-Koszul algebra $\m$ is a \K module over the even Yoneda algebra $\Eev(\m)$.

math.RA↗