检索结果-南通市图书馆

Acta Mathematica Scientia 2011年第6期31卷 2122-2130页

作者： Bashir Ahmad Juan J. Nieto Ahmed Alsaedi department of Mathematics Faculty of ScienceKing Abdulaziz University departamento de Anlisis matemtico Facultad de MatemticasUniversidad de Santiago de Compostela

In this paper, we study a boundary value problem of nonlinear fractional dif- ferential equations of order q （1 〈 q 〈 2） with non-separated integral boundary conditions. Some new existence and uniqueness results are obtained by using some standard fixed point theorems and Leray-Schauder degree theory. Some illustrative examples are also presented. We extend previous results even in the integer case q = 2.

关键词： fractional differential equations non-separated integral boundary conditions contraction principle Krasnoselskii's fixed point theorem LeraySchauder degree

CONTROLLABILITY AND OPTIMALITY OF LINEAR TIME-INVARIANT NEUTRAL CONTROL SYSTEMS WITH DIFFERENT FRACTIONAL ORdeRS

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2015年第5期35卷 1003-1013页

作者：丁小丽 Juan J.NIETO department of Mathematics Xi’an Polytechnic University departamento de Análisis matemático Facultad de MatemáticasUniversidad de Santiago de Compostela department of Mathematics Faculty of Science King Abdulaziz University

Control systems governed by linear time-invariant neutral equations with different fractional orders are considered. Sufficient and necessary conditions for the controllability of those systems are established. The existence of optimal controls for the systems is given. Finally, two examples are provided to show the application of our results.

关键词： controllability optimality neutral equations different fractional orders

A SHORT NOTE ABOUT EXPOSED POINTS IN REAL BANACH SPACES

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 2008年第4期28卷 797-800页

作者： Antonio Aizpuru Francisco J Garcia-Pacheco departamento de matemá ticas Universidad de Cá diz department of Mathematical Sciences Kent State University

We express the set of exposed points in terms of rotund points and non-smooth *** long as we have Banach spaces each time＂bigger＂,we consider sets of non-smooth points each time＂smaller＂.

关键词： Exposed point exposed face rotund point smooth point

On the Differential Polynomial of a Graph

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2019年第3期35卷 338-354页

作者： Ludwin A.BASILIO-HERNáNdeZ Walter CARBALLOSA Jesús LEA?OS José M.SIGARRETA Unidad Académica de matemáticas Universidad Autónoma de Zacatecas Calzada Solidaridad entronque Paseo a la Bufa department of Mathematics and Statistics Florida International University department of Mathematics Miami Dade College Facultad de matemáticas Universidad Autónoma de Guerrero

We introduce the differential polynomial of a graph. The differential polynomial of a graph G of order n is the polynomial B(G; x) :=∑?(G)k=-nB_k(G) x^(n+k), where B_k(G) denotes the number of vertex subsets of G with differential equal to k. We state some properties of B(G;x) and its *** particular, we compute the differential polynomial for complete, empty, path, cycle, wheel and double star graphs. We also establish some relationships between B(G; x) and the differential polynomials of graphs which result by removing, adding, and subdividing an edge from G.

关键词： Graph polynomial differential of a graph

Type Ⅱ Blow-up in the 5-dimensional Energy Critical Heat Equation

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2019年第6期35卷 1027-1042页

作者： Manuel del PINO Monica MUSSO Jun Cheng WEI department of Mathematical Sciences University of Bath departamento de Ingeniería matemática-CMM Universidad de Chile departamento de matemáticas Universidad Católica de Chile department of Mathematics University of British Columbia

We consider the Cauchy problem for the energy critical heat equation ■ in dimension n = 5. More precisely we find that for given points q_1, q_2,..., q_k and any sufficiently small T > 0 there is an initial condition u0 such that the solution u(x, t) of(0.1) blows-up at exactly those k points with rates type Ⅱ, namely with absolute size ～(T-t)^(-α) for α >3/4. The blow-up profile around each point is of bubbling type, in the form of sharply scaled Aubin–Talenti bubbles.

关键词： Singularity formation bubbling phenomena critical parabolic equations

Hölder,Sobolev,weak-type and BMO estimates in mixed-norm with weights for parabolic equations

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2021年第1期64卷 129-154页

作者： Pablo Raúl Stinga José L.Torrea department of Mathematics Iowa State UniversityAmesIA50011USA departamento de matemáticas Universidad Autónoma de MadridMadrid28049Spain

We prove weighted mixed-norm Lqt(W2,px)and Lqt(C2,αx)estimates for 10,x∈Rn.x∈Rn,The coefficients a(t)=(aij(t))are just bounded,measurable,symmetric and uniformly ***,we show strong,weak type and BMO-Sobolev estimat... 详细信息

We prove weighted mixed-norm Lqt(W2,px)and Lqt(C2,αx)estimates for 1derivatives,for the solutions u=u(t,x)to parabolic equations of the form∂tu−aij(t)∂iju+u=f,t∈,x∈n and for the Cauchy problem{∂tv−aij(t)∂ijv+v=fv(0,x)forfort>0,x∈Rn.x∈Rn,The coefficients a(t)=(aij(t))are just bounded,measurable,symmetric and uniformly ***,we show strong,weak type and BMO-Sobolev estimates with parabolic Muckenhoupt *** is quite remarkable that most of our results are new even for the classical heat equation∂tu−Δu+u=f.

关键词： Calderón-Zygmund parabolic singular integrals weak type and BMO estimates representation formulas parabolic equations mixed-norm Sobolev and Schauder estimates

Impulsive perturbation and bifurcation of solutions for a model of chemostat with variable yield

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2009年第7期30卷 933-944页

作者：张弘 Paul Georgescu Juan J.Nieto 陈兰荪 department of Mathematics Jiangsu University department of Mathematics and Mathematical Statistics Ume University department of Mathematics "Gh.Asachi" Technical University of Iasi departamento de Análisis matemático Facultad de Matemáticas Universidadde Santiago de Compostela Institute of Mathematics Chinese Academy of Sciences

In this paper, we consider a variable yield model of a single-species growth in a well-stirred tank containing fresh medium, assuming the instances of time as triggering factors in which the nutrient refilling process and the removal of microorganisms by the uptake of lethal external antibiotic are initiated. It is also assumed that the periodic nutrient refilling and the periodic antibiotic injection occur with the same periodicity, but not simultaneously. The model is then formulated in terms of autonomous differential equations subject to impulsive perturbations. It is observed that either the population of microorganisms essentially washes out, or more favorably, the system is permanent. To describe this dichotomy, some biologically significant integral conditions are introduced. Further, it is shown that in a certain critical situation, a nontriviai periodic solution emerges via a bifurcation phenomenon. Finally, the dynamics of the model is illustrated with numerical experiments and computer simulations.

关键词： chemostat impulsive differential equation permanence extinction fixedpoint approach bifurcation

The tensor embedding for a Grothendieck cosmos

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2023年第11期66卷 2471-2494页

作者： Henrik Holm Sinem Odabasi department of Mathematical Sciences University of CopenhagenCopenhagen 02100Denmark Instituto de Ciencias Físicas y matemáticas Universidad Austral de ChileValdivia 5090000Chile

While the Yoneda embedding and its generalizations have been studied extensively in the literature,the so-called tensor embedding has only received a little *** this paper,we study the tensor embedding for closed symmetric monoidal categories and show how it is connected to the notion of geometrically purity,which has recently been investigated in the works of Enochs et al.(2016)and Estrada et al.(2017).More precisely,for a Grothendieck cosmos,i.e.,a bicomplete Grothendieck category V with a closed symmetric monoidal structure,we prove that the geometrically pure exact category(V,ε■)has enough relative injectives;in fact,every object has a geometrically pure injective *** also show that for some regular cardinalλ,the tensor embedding yields an exact equivalence between(V,ε■)and the category ofλ-cocontinuous V-functors from Presλ(V)to V,where the former is the full V-subcategory ofλ-presentable objects in *** many cases of interest,λcan be chosen to be■0 and the tensor embedding identifies the geometrically pure injective objects in V with the(categorically)injective objects in the abelian category of V-functors from fp(V)to *** we explain,the developed theory applies,e.g.,to the category Ch(R)of chain complexes of modules over a commutative ring R and to the category Qcoh(X)of quasi-coherent sheaves over a(suitably nice)scheme X.

关键词： enriched functor exact category (pre)envelope (pure)injective object purity symmetric monoidal category tensor embedding Yoneda embedding

Gorenstein injective sheaves

在线全文

学校读者我要写书评

暂无评论

Frontiers of Mathematics in China 2017年第1期12卷 87-95页

作者： Sergio ESTRADA Alina IACOB departamento de matem~ticas Universidad de Murcia Murcia 30100 Spain department of Mathematical Sciences Georgia Southern University Statesboro GA 3O460 USA

We define Gorenstein injective quasi-coherent sheaves, and prove that the notion is local in case the scheme is Gorenstein. We also give a new characterization of a Gorenstein scheme in terms of the total acyclicity o... 详细信息

关键词： Gorenstein injective Noetherian scheme

Local Isoperimetric Inequalities for Sectors on Surfaces and Cones

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2007年第7期23卷 1317-1326页

作者： Fernando GIMNEZ Javier Orengo VALVERde department de matemdtica Aplicada University Politécnica de ValenciaCamino de Vera s/n46022SPAIN department de matemáticas University de Castilla la ManchaAvda.de Espaas/n02071AlbaceteSpain

On surfaces we give conditions under which the solution of a restricted local isoperimetric problem for sectors with small solid angle is the circular sector and we characterize these surfaces. Also we study this prob... 详细信息

关键词： isoperimetric cones solid angle