共查询到20条相似文献,搜索用时 15 毫秒
1.
D. A. Stepanov 《Proceedings of the American Mathematical Society》2008,136(8):2647-2654
It is well known that the exceptional set in a resolution of a rational surface singularity is a tree of rational curves. We generalize the combinatoric part of this statement to higher dimensions and show that the highest cohomologies of the dual complex associated to a resolution of an isolated rational singularity vanish. We also prove that the dual complex associated to a resolution of an isolated hypersurface singularity is simply connected. As a consequence, we show that the dual complex associated to a resolution of a 3-dimensional Gorenstein terminal singularity has the homotopy type of a point.
2.
We classify the singularities of a surface ruled by conics: they are rational double points of type A n or D n . This is proved by showing that they arise from a precise series of blow-ups of a suitable surface geometrically ruled by conics. We determine also the family of such surfaces which are birational models of a given surface ruled by conics and obtained in a “minimal way” from it. 相似文献
3.
In previous papers, the authors computed the Poincaré series of some (multi-index) filtrations on the ring of germs of functions on a rational surface singularity. These Poincaré series were expressed as the integer parts of certain fractional power series, whose interpretation was not given. In this paper, we show that, up to a simple change of variables, these fractional power series are reductions of the equivariant Poincaré series for filtrations on the ring of germs of functions on the universal Abelian cover of the surface. We compute these equivariant Poincaré series. 相似文献
4.
Elmar Grosse-Klnne 《Finite Fields and Their Applications》2007,13(4):896-921
Let be an abelian prime-to-p Galois covering of smooth schemes over a perfect field k of characteristic . Let Y be a smooth compactification of such that is a normal crossings divisor on Y. We describe a logarithmic F-crystal on Y whose rational crystalline cohomology is the rigid cohomology of X, in particular provides a natural -lattice inside the latter; here W is the Witt vector ring of k. If a finite group G acts compatibly on X, and Y then our construction is G-equivariant. As an example we apply it to Deligne–Lusztig varieties. For a finite field k, if is a connected reductive algebraic group defined over k and a k-rational torus satisfying a certain standard condition, we obtain a meaningful equivariant -lattice in the cohomology (ℓ-adic or rigid) of the corresponding Deligne–Lusztig variety and an expression of its reduction modulo p in terms of equivariant Hodge cohomology groups. 相似文献
5.
6.
Ali-Amir Husain 《Journal of Functional Analysis》2006,231(1):157-176
By analogy with the join in topology, the join A*B for operator algebras A and B acting on Hilbert spaces H and K, respectively, was defined by Gilfeather and Smith (Amer. J. Math. 116 (1994) 541-561). Assuming that K is finite dimensional, they calculated the Hochschild cohomology groups for A*B with coefficients in L(K⊕H). We assume that A is a maximal abelian von Neumann algebra acting on H, A is a subalgebra of , and B is an ultraweakly closed subalgebra of Mn(A) containing A⊗1n. We show that B may be decomposed into a finite sum of free modules. In this context, we redefine the join of A and B, generalize the calculations of Gilfeather and Smith, and calculate , for all m?0. 相似文献
7.
Kamal Bahmanpour Reza Naghipour 《Proceedings of the American Mathematical Society》2008,136(7):2359-2363
In this note we show that if is an ideal of a Noetherian ring and is a finitely generated -module, then for any minimax submodule of the -module is finitely generated, whenever the modules are minimax. As a consequence, it follows that the associated primes of are finite. This generalizes the main result of Brodmann and Lashgari (2000).
8.
Thomas Krainer 《Mathematische Nachrichten》2010,283(12):1680-1695
We show the completeness of the system of generalized eigenfunctions of closed extensions of elliptic cone operators under suitable conditions on the symbols (© 2010 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献
9.
《Journal of Pure and Applied Algebra》2022,226(6):106959
The sectional category of a subgroup inclusion can be defined as the sectional category of the corresponding map between Eilenberg–MacLane spaces. We extend a characterization of topological complexity of aspherical spaces given by Farber, Grant, Lupton and Oprea to the context of sectional category of subgroup inclusions and investigate it by means of Adamson cohomology theory. 相似文献
10.
A. Blanco 《Journal of Functional Analysis》2011,261(1):111-148
We investigate the simplicial cohomology of certain Banach operator algebras. The two main examples considered are the Banach algebra of all bounded operators on a Banach space and its ideal of approximable operators. Sufficient conditions will be given forcing Banach algebras of this kind to be simplicially trivial. 相似文献
11.
《Mathematische Nachrichten》2018,291(2-3):245-263
The aim of this paper is to study mixed multiplier ideals associated with a tuple of ideals in a two‐dimensional local ring with a rational singularity. We are interested in the partition of the real positive orthant given by the regions where the mixed multiplier ideals are constant. In particular we reveal which information encoded in a mixed multiplier ideal determines its corresponding jumping wall and we provide an algorithm to compute all the constancy regions, and their corresponding mixed multiplier ideals, in any desired range. 相似文献
12.
13.
Ken-ichiroh Kawasaki 《Proceedings of the American Mathematical Society》1996,124(11):3275-3279
In this note we show that, if is an ideal of dimension 1 of an analytically irreducible local ring, then the Bass numbers of local cohomology modules with support in are finite.
14.
Seong-Hun Paeng 《Proceedings of the American Mathematical Society》2003,131(8):2577-2583
Gromov conjectured that the fundamental group of a manifold with almost nonnegative Ricci curvature is almost nilpotent. This conjecture is proved under the additional assumption on the conjugate radius. We show that there exists a nilpotent subgroup of finite index depending on a lower bound of the conjugate radius.
15.
We show that the only rational homology spheres which can admit almost complex structures occur in dimensions two and six. Moreover, we provide infinitely many examples of six-dimensional rational homology spheres which admit almost complex structures, and infinitely many which do not. We then show that if a closed almost complex manifold has sum of Betti numbers three, then its dimension must be a power of two. 相似文献
16.
Kathrin Berkner 《Proceedings of the American Mathematical Society》1999,127(2):425-435
We present a complete classification of the zero set of a function which is a convolution with the Gaussian kernel. In the first part, we calculate the Taylor expansion of the convolution in a critical point. In the second part, we resolve the singularity with the help of the general Newton process which yields the Puiseux expansions for the solutions. Finally, we describe the resolved singularity in terms of Hermite polynomials.
17.
We investigate low degree rational cohomology groups of smooth compactifications of moduli spaces of curves with level structures.
In particular, we determine
Hk([`(S)]g, \mathbb Q){H^k\left({\bar S}_{g}, {\mathbb Q}\right)} for g ≥ 2 and k ≤ 3, where [`(S)]g{{\bar S}_{g}} denotes the moduli space of spin curves of genus g. 相似文献
18.
We show how some differential geometric ideas help to resolve some singularities of ordinary differential systems. Hence a
singular problem is replaced by a regular one, which facilitates further analysis of the system. The methods employed are
constructive and the regularized systems can also be used for numerical computations.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
19.
《Journal of Pure and Applied Algebra》2023,227(7):107318
We establish some upper and lower bounds of the rational topological complexity for certain classes of elliptic spaces. Our techniques permit us in particular to show that the rational topological complexity coincides with the dimension of the rational homotopy for some special families of coformal elliptic spaces. 相似文献
20.
V. A. Krasnov 《Mathematical Notes》1999,66(2):171-173
It is proved that there is only one relation between the homology classes determined by the real points of a special real
algebraic variety. This relation is equal to the sum of all the homology classes.
Translated fromMatematicheskie Zametki, Vol. 66, No. 2, pp. 216–219, August, 1999. 相似文献