共查询到20条相似文献,搜索用时 273 毫秒
1.
ON SYMMETRIC SCALAR CURVATURE ON 总被引:1,自引:0,他引:1
JI Min 《数学年刊B辑(英文版)》1999,20(3):325-330
1.IntroductionGivenacontinuousfunctionRonthestandardsphereS',itisaninterestingproblemwhetherRcanbethescalarcurvatureofsomemetricgwhichispointwiseconformaltothestandardmetricgoonS2.Ifwesetg~e"go,whereuisafunctiononS',theproblemisequivalenttothesolvabilityofthefollowingPDE:--A..u 2--Re"=0,onS2.(l'1)KazdanandWarner[9]pointedoutthatitmaybeinsolvable.Inthelastfewyears,alotofworkhasbeendonetosolveproblem(l.l),especiallywhenRpossessessomekindsofsymmetries.AfterthepioneerworkduetoMoser[lo]forthe… 相似文献
2.
3.
D. VENDRUSCOLO 《数学年刊B辑(英文版)》2005,26(2):315-322
§ 1 . IntroductionQuestions about bounds for indices ?rst appeared in the ?xed point context. The ?rstresults appeared in studies of surface homeomorphisms (see [13, 18, 19]). In [12, 14] and[15] some results about bounds for Nielsen ?xed point class ind… 相似文献
4.
《Quaestiones Mathematicae》2013,36(4):339-350
Abstract In this note we prove an extension of B. de Pagter's theorem (positive, compact, irreducible operators on Banach lattices are not quasi-nilpotent) for positive, band irreducible operators on Banach lattices satisfying some additional conditions. 相似文献
5.
6.
本文研究了一类曲面的无穷小Ⅰ(Ⅲ)—等距,得到了两个整体定理,并由此证明了在适当的边界条件下,特殊Weingarten曲面M的无穷小Ⅰ(Ⅲ)—等距Φ是关于M的无穷小刚体运动。 相似文献
7.
本文讨论G逆半群上的同余,文中给出刻划p^k,pk,p^T,pT的方法,并用来讨论半格同余,纯幂同余,群同余及幂等元分离同余。 相似文献
8.
9.
10.
This article considers a class of bottleneck capacity expansion problems. Such problems aim to enhance bottleneck capacity to a certain level with minimum cost. Given a network G(V, A, C) consisting of a set of nodes V= {v1,v2,…,vn},a set of arcs A ■ {(vi, vj) | i=1,2,…, n;j=1,2,…,n} and a capacity vector C. The component cij of C is the capacity of arc (vi ,vj). Define the capacity of a subset A' of A as the minimum capacity of the arcs in A, the capacity of a family F of subsets of A is the maximum capacity of its members. There are two types of expanding models. In the arc-expanding model, the unit cost to increase the capacity of arc (vi, vj) is wij. In the node-expanding model, it is assumed that the capacities of all arcs (vi,vj) which start at the same node vi should be increased by the same amount and that the unit cost to make such expansion is wi. This article considers three kinds of bottleneck capacity expansion problems (path, spanning arborescence and maximum flow) in both expanding models. For each kind of expansion problems, this article discusses the characteristics of the problems and presents several results on the complexity of the problems. 相似文献
11.
12.
13.
14.
15.
《代数通讯》2013,41(8):3559-3570
This paper concerns some of the conditions satisfied by additive group actions on complex affine space which can be written locally as a translation of a variable. Assume X is the affine variety C n , Ga = (C, +), and σ : Ga × X → X is the action defined by a group monomorphism G a → Aut C X. If σ is locally trivial, then the action satisfies what is termed a “GICO” condition. It will be shown that a large class of Ga -actions on C 4, that is, fixed-point free, “twin-triangular” actions with finitely-generated rings of invariants, are at least GICO. Remaining questions are discussed. 相似文献
16.
17.
18.
令Δ_n=sum from j=1 to (?)((?)~2)/((?)x_j~2)为 R~n 上的 Laplace 算子,设Δ_n~ku(x_1,…,x_n)=0,(x_1…,x_n)∈R~n,k≥1,即 u(x_1,…,x_n)是 k 级调和函数。早已知道,u 是实解析函数,因而可延拓成 R~n 在 C~n 的一个邻域的解析函数 u(z_1,…,z_n)(可参看[1])。在这篇短文中,我们将证明 u 是整函数,即可延拓成 C~n 上的解析函数(定理1)。设 u(x_1,…,x_n)是 R~n 上的调和函数,则因 u(z_1,…,z_n)是 C~n 上的解析函数,故sum from j=1 to n ((?)~u)/((?)z_j~2)是 C~n 上的解析函数,因它在 R~n 上为零,故在 C~n 上为零。因此,我们的结果表明R~n 上的调和函数空间与 C~n 上满足:sum from j=1 to n ((?)~2u)/((?)z_j~2)=0的解析函数 u(我们不妨称之为复调和函数)的空间是一致的。同理 R~(n 1)上对最后一个变量为偶的调和函数空间与 C~(n 1)上对最 相似文献
19.
《Quaestiones Mathematicae》2013,36(3):339-348
Abstract For n a positive integer and v a vertex of a graph G, the nth order degree of v in G, denoted by degnv, is the number of vertices at distance n from v. The graph G is said to be nth order regular of degree k if, for every vertex v of G, degnv = k. The following conjecture due to Alavi, Lick, and Zou is proved: For n ≥ 2, if G is a connected nth order regular graph of degree 1, then G is either a path of length 2n—1 or G has diameter n. Properties of nth order regular graphs of degree k, k ≥ 1, are investigated. 相似文献
20.
XIE Qihong 《数学年刊B辑(英文版)》2005,26(1):105-110
The author gives a counterexample and some conclusions for effective non-vanishing of Weil divisors on algebraic surfaces. 相似文献