Restricted Homological Dimensions of Complexes

We define and study the notions of restricted Tor-dimension and Ext-dimension for unbounded complexes of left modules over associative rings. We show that, for a right (respectively, left) homologically bounded complex, our definition agrees with the small restricted flat (respectively, injective) dimension defined by Christensen et al. Furthermore, we show that the restricted Tor-dimension defined in this paper is a refinement of the Gorenstein flat dimension of an unbounded complex in some sense. In addition, we give some results concerning restricted homological dimensions under a base change over commutative Noetherian rings.     

Critical Exponents of Quasilinear Parabolic Equations

In this paper we study the critical exponents of the Cauchy problem in Rⁿ of the quasilinear singular parabolic equations: u_t = div(|∇u|^m − 1∇u) + t^s|x|^σu^p, with non-negative initial data. Here s ≥ 0, (n − 1)/(n + 1) < m < 1, p > 1 and σ > n(1 − m) − (1 + m + 2s). We prove that p_c ≡ m + (1 + m + 2s + σ)/n > 1 is the critical exponent. That is, if 1 < p ≤ p_c then every non-trivial solution blows up in finite time, but for p > p_c, a small positive global solution exists.     

Morse Index and Critical Groups for p-Laplace Equations with Critical Exponents

In this work we consider a class of Euler functionals defined in Banach spaces, associated to quasilinear elliptic problems involving the critical Sobolev exponent. We perform critical groups estimates via the Morse index. Dedicated to the memory of Professor Aldo Cossu The research of the authors was supported by the MIUR project “Variational and topological methods in the study of nonlinear phenomena” (PRIN 2005).     

Lipschitz Invariance of Critical Exponents on Besov Spaces

In this paper we prove that the critical exponents of Besov spaces on a compact set possessing an Ahlfors regular measure is an invariant under Lipschitz transforms. Under mild conditions, the critical exponent of Besov spaces of certain self-similar sets coincides with the walk dimension, which plays an important role in the analysis on fractals. As an application, we show examples having different critical exponents are not Lipschitz equivalent.     

Critical Fujita Exponents for Localized Reaction Diffusion Systems

§１．　ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｉｓｐａｐｅｒｄｅａｌｓｗｉｔｈｔｈｅｆｏｌｌｏｗｉｎｇｉｎｉｔｉａｌｖａｌｕｅｐｒｏｂｌｅｍｕｔ＝Δｕ＋ｖｐ１（０,ｔ）ｖｒ１（ｘ,ｔ）,ｖｔ＝Δｖ＋ｕｐ２（０,ｔ）ｕｒ２（ｘ,ｔ）,ｕ（ｘ,０）＝ｕ０（ｘ）,ｖ（ｘ,０）＝ｖ０（ｘ）,　　ｘ∈ＲＮ,ｔ＞０,ｘ∈ＲＮ,ｔ＞０,ｘ∈ＲＮ,（１）ｗｈｅｒｅＮ１,ｐｉ＞０,ｒｉ１,ｉ＝１,２,ｕ０（ｘ）０ａｎｄｖ０（ｘ）０ａｒｅｎｏｎｎｅｇａｔｉｖｅｃｏｎｔｉｎｕｏｕｓ,ａｎｄｂｏｕｎｄｅｄｆｕｎｃｔｉｏｎ…     

Critical Percolation and the Minimal Spanning Tree in Slabs

The minimal spanning forest on ?^d is known to consist of a single tree for d ≤ 2 and is conjectured to consist of infinitely many trees for large d . In this paper, we prove that there is a single tree for quasi‐planar graphs such as ?² × {0,…,k }^d?2. Our method relies on generalizations of the “gluing lemma” of Duminil‐Copin, Sidoravicius, and Tassion. A related result is that critical Bernoulli percolation on a slab satisfies the box‐crossing property. Its proof is based on a new Russo‐Seymour‐Welsh‐type theorem for quasi‐planar graphs. Thus, at criticality, the probability of an open path from 0 of diameter n decays polynomially in n . This strengthens the result of Duminil‐Copin et al., where the absence of an infinite cluster at criticality was first established. © 2017 Wiley Periodicals, Inc.     

Critical Fujita Exponents for Nonlocal Reaction Diffusion Systems

In this paper, we prove the existence of critical Fujita exponents for a class of nonlocal reaction diffusion systems. And it is proved that the critical Fujita exponents belong to the blow up case.     

一类反应扩散系统的不同时爆破临界指标(英文)

本文讨论了一类反应扩散方程组齐次第一初边值问题u_t=△u+u~mv~p,v_t=△v+u~qv~n的不同时爆破临界指标问题.在一定初值条件下,本文给出了径向解的四种同时、不同时爆破现象:存在初值使得同时爆破或不同时爆破发生;任何爆破均是同时或不同时的.通过对指标参数的完整分类给出了四种爆破现象的充分必要条件,并且得到了解的全部爆破速率估计.所得结果推广了以前的相应工作.     

Stability and Unconditional Uniqueness of Solutions for Energy Critical Wave Equations in High Dimensions

In this paper we establish a complete local theory for the energy-critical nonlinear wave equation (NLW) in high dimensions ? × ? ^d with d ≥ 6. We prove the stability of solutions under the weak condition that the perturbation of the linear flow is small in certain space-time norms. As a by-product of our stability analysis, we also prove local well-posedness of solutions for which we only assume the smallness of the linear evolution. These results provide essential technical tools that can be applied towards obtaining the extension to high dimensions of the analysis of Kenig and Merle [17 Kenig , C.E. , Merle , F. ( 2008 ). Global well-posedness, scattering and blow-up for the energy critical focusing non-linear wave equation . Acta Math. 201 : 147 – 212 .[Crossref], [Web of Science ®] , [Google Scholar]] of the dynamics of the focusing (NLW) below the energy threshold. By employing refined paraproduct estimates we also prove unconditional uniqueness of solutions for d ≥ 6 in the natural energy class. This extends an earlier result by Planchon [26 Planchon , F. ( 2003 ). On uniqueness for semilinear wave equations . Math. Z. 244 : 587 – 599 .[Web of Science ®] , [Google Scholar]].     

Blow Up of Solutions to Semilinear Wave Equations with Critical Exponent in High Dimensions

In this paper, the author considers the Cauchy problem for semilinear wave equations with critical exponent in n≥4 space dimensions. Under some positivity conditions on the initial data, it is proved that there can be no global solutions no matter how small the initial data are.     

带有临界Sobolev指数的奇异双调和问题

LetΩR~N be a smooth bounded domain such that 0∈Ω,N≥5,2~*:=(2N)/(N-4) is the critical Sobolev exponent,and f(x) is a given function.By using the variational methods, the paper proves the existence of solutions for the singular critical in the homogeneous problemΔ~u-μu/(|x|~4)=|u|~(2~*-2)u f(x) with Dirichlet boundary condition on Ωunder some assumptions on f(x) andμ.     

Sem ilinear Equationswith CriticalExponentsonthe Heisenberg Group

§１．　ＩｎｔｒｏｄｕｃｔｉｏｎＬｅｔΩｂｅａｂｏｕｎｄｅｄｓｍｏｏｔｈｄｏｍａｉｎｉｎｔｈｅＨｅｉｓｅｎｂｅｒｇｇｒｏｕｐＨｎ，ｗｅａｒｅｃｏｎｃｅｒｎｅｄｗｉｔｈｔｈｅｐｒｏｂｌｅｍｏｆｓｅｍｉｌｉｎｅａｒｓｕｂｅｌｌｉｐｔｉｃＬａｐｌａｃｅｅｑｕａｔｉｏｎ－ΔＨｎｕ＝ｕｐ＋ｆ（ｘ，ｕ），ｉｎΩ，ｕ＞０，　　　　ｉｎΩ，（１．１）ｕ＝０，　　　　ｏｎΩ，ｗｈｅｒｅｐｉｓａｒｅａｌｎｕｍｂｅｒ，ｆ（ｘ，ｙ）ｓａｔｉｓｆｉｅｓｓｕｉｔａｂｌｅａｓｓｕｍｐｔｉｏｎｓ（ｓｅｅｂｅｌｏｗｓｅｃｔｉｏ…     

A Note About Critical Percolation on Finite Graphs

In this note we study the geometry of the largest component C₁\mathcal {C}_{1} of critical percolation on a finite graph G which satisfies the finite triangle condition, defined by Borgs et al. (Random Struct. Algorithms 27:137–184, 2005). There it is shown that this component is of size n ^2/3, and here we show that its diameter is n ^1/3 and that the simple random walk takes n steps to mix on it. By Borgs et al. (Ann. Probab. 33:1886–1944, 2005), our results apply to critical percolation on several high-dimensional finite graphs such as the finite torus \mathbbZ_n^d\mathbb{Z}_{n}^{d} (with d large and n→∞) and the Hamming cube {0,1} ⁿ .     

Large Critical Exponents for Some Second Order Uniformly Elliptic Operators

In this paper we investigate the critical exponents of two families of Pucci's extremal operators. The notion of critical exponent that we have chosen for these fully nonlinear operators which are not variational is that of threshold between existence and nonexistence of the solutions for semilinear equations with pure power nonlinearities. Interesting new exponents appear in this context.     

Nontrivial Solutions of Semilinear Elliptic Equations Involving Critical Sobolev Exponents

ＮｏｎｔｒｉｖｉａｌＳｏｌｕｔｉｏｎｓｏｆＳｅｍｉｌｉｎｅａｒＥｌｌｉｐｔｉｃＥｑｕａｔｉｏｎｓＩｎｖｏｌｖｉｎｇＣｒｉｔｉｃａｌＳｏｂｏｌｅｖＥｘｐｏｎｅｎｔｓＨａｎＪｉａｎｌｏｎｇ（韩建龙）（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｈｅｍａｔｉｃｓ，Ｔｉａ...     

全空间上带Hardy-Sobolev项的拟线性椭圆方程解的存在性

讨论了全空间上一类带Hardy-Sobolev项的拟线性椭圆问题,利用集中紧原理和适当的实验函数,得到并验证了(PS)_c条件,从而证明了该问题非平凡解的存在性.     

高维空间的拟正则映照

将所有维数的 Beltrami方程组 Dtf· Df =J2 /n G化为一个“Beltrami方程”并利用它研究了 Bel-trami方程组的解的正则性 ,得到一个比文献 [8]更大的正则性区间 .     

高维空间的拟正则映照

１引言 众所周知,设Ω是一个复平面区域,则中的Ｂｅｌｔｒａｍｉ方程：的解ｗ＝ｆ（ｚ）称为上的　正则函数,当ｗ＝ｆ（ｚ）是同胚的时候,称为　共形映照．正则函数和什共形映照在复分析中有重要的理论意义和广泛的应用,并已被深入系统的研究［１－５］．如何将它们推广到高维长期受到人们的关注,并已有了一些重要的工作．最近Ｔ．Ｉｗａｎｉｅｃ和Ｇ．Ｍａｒｔｉｎ得到了Ｂｅｌｔｒａｍｉ方程和正则函数的正则性理论在偶数维空间中的相应推广,这是拟正则函数的正则性理论研究中的一个重要发展［６］;之后Ｔ．Ｉｗａｎｉｅｃ应用变…     

Critical Exponents for Fast Diffusion Equations with Nonlinear Boundary Sources

In this paper,we study the large time behavior of solutions to a class of fast diffusion equations with nonlinear boundary sources on the exterior domain of the unit ball.We are interested in the critical global exponent q_o and the critical Fujita exponent q_c for the problem considered,and show that q_o=q_c for the multidimensional Non-Newtonian polytropic filtration equation with nonlinear boundary sources,which is quite different from the known results that q_o〈q_c for the onedimensional case;moreover,the value is different from the slow case.     

具Hardy-Sobolev界指数的非齐次椭圆方程的正解

讨论-类具Hardy-Sobolev临界指数的非齐次半线性椭圆方程,通过应用Lions集中紧性原理建立了S_μ(Q)的极小函数,再结合Ekeland变分原理、山路引理和Nehari流形的分析方法证明了方程在适当条件下正解的存在性与多重性.