共查询到20条相似文献,搜索用时 0 毫秒
1.
Cristina Martínez 《Journal of Algebra》2008,319(10):4391-4403
2.
A 2003 counterexample to a conjecture of Auslander brought attention to a family of rings—colloquially called AC rings—that satisfy a natural condition on vanishing of cohomology. Several results attest to the remarkable homological properties of AC rings, but their definition is barely operational, and it remains unknown if they form a class that is closed under typical constructions in ring theory. In this paper, we study transfer of the AC property along local homomorphisms of Cohen–Macaulay rings. In particular, we show that the AC property is preserved by standard procedures in local algebra. Our results also yield new examples of Cohen–Macaulay AC rings. 相似文献
3.
4.
5.
Dmitri I. Panyushev 《Selecta Mathematica, New Series》2010,16(2):315-342
Let G be a simple algebraic group and B a Borel subgroup. We consider generalisations of Lusztig’s q-analogues of weight multiplicity, where the set of positive roots is replaced with the multiset of weights of a B-submodule N of an arbitrary finite-dimensional G-module V. The corresponding polynomials in q are called generalised Kostka–Foulkes polynomials (gKF). We prove vanishing theorems for the cohomology of line bundles on
G ×
B
N and derive from this a sufficient condition for the non-negativity of the coefficients of gKF. We also consider in detail
the case in which V is the simple G-module whose highest weight is the short dominant root and N is the B-submodule whose weights are all short positive roots. 相似文献
6.
Cheng-Yong Du 《Archiv der Mathematik》2016,107(5):473-485
In this note, for a closed symplectic orbifold \({(\mathsf{X},\omega)}\), we study the Lefschetz property of the de Rham cohomology ring \({(H^{*}_{dR}(\mathsf{X}),\wedge)}\) and the Chen–Ruan cohomology ring \({(H^{*}_{CR}(\mathsf{X}),\cup_{CR})}\), and the relation of these Lefschetz properties with the existence of symplectic harmonic representatives and the \({d\delta}\)-Lemma on \({(\mathsf{X},\omega)}\) and \({(\Lambda\mathsf{X},e^{*}\omega)}\). 相似文献
7.
We give bounds on the first non-zero eigenvalue of the scalar Laplacian for both the Page and the Chen–LeBrun–Weber Einstein metrics. One notable feature is that these bounds are obtained without explicit knowledge of the metrics or numerical approximation to them. Our method also allows the estimation of the invariant part of the spectrum for both metrics. We go on to discuss an application of these bounds to the linear stability of the metrics. We also give numerical evidence to suggest that the bounds for both metrics are extremely close to the actual eigenvalue. 相似文献
8.
Nicola Pagani 《Advances in Mathematics》2012,229(3):1643-1687
In this work we describe the Chen–Ruan cohomology of the moduli stack of smooth and stable genus 2 curves with marked points. In the first half of the paper we compute the additive structure of the Chen–Ruan cohomology ring for the moduli stack of stable n-pointed genus 2 curves, describing it as a rationally graded vector space. In the second part we give generators for the even Chen–Ruan cohomology ring as an algebra on the ordinary cohomology. 相似文献
9.
Dzhaparidze and Spreij (Stoch Process Appl, 54:165–174, 1994) showed that the quadratic variation of a semimartingale can be approximated using a randomized periodogram. We show that the same approximation is valid for a special class of continuous stochastic processes. This class contains both semimartingales and non-semimartingales. The motivation comes partially from the recent work by Bender et al. (Finance Stoch, 12:441–468, 2008), where it is shown that the quadratic variation of the log-returns determines the hedging strategy. 相似文献
10.
We determine the cohomology of the Losev–Manin moduli space ${\overline{M}_{0, 2 | n}}$ of pointed genus zero curves as a representation of the product of symmetric groups ${\mathbb{S}_2 \times \mathbb{S}_n}$ . 相似文献
11.
Michael Finkelberg Victor Ginzburg Andrei Ionov Alexander Kuznetsov 《Selecta Mathematica, New Series》2016,22(4):2491-2534
We study the natural Gieseker and Uhlenbeck compactifications of the rational Calogero–Moser phase space. The Gieseker compactification is smooth and provides a small resolution of the Uhlenbeck compactification. We use the resolution to compute the stalks of the IC-sheaf of the Uhlenbeck compactification. 相似文献
12.
13.
We prove, on one hand, that for a convenient body force with values
in the distribution space (H
-1(D))
d
, where D is the geometric
domain of the fluid, there exist a velocity u and a pressure p
solution of the stochastic Navier–Stokes equation in dimension
2, 3 or 4.
On the other hand, we prove that, for a body force with values in the
dual space V of the divergence free subspace V of (H
1
0(D))
d
,
in general it is not possible to solve the stochastic Navier–Stokes
equations.
More precisely, although such body forces have been considered, there
is no topological space in which Navier–Stokes equations could be
meaningful for them. 相似文献
14.
15.
《Topology and its Applications》2000,100(2-3):133-150
We use the Eilenberg–Moore spectral sequence to study torsion phenomena in the integral cohomology of finite loop spaces with maximal torus generalizing some results for compact Lie groups due to Kac. 相似文献
16.
We consider a mixed Brownian–fractional-Brownian model of a financial market. The class of self-financing strategies is restricted to Markov-type smooth functions. It is proved that such strategies satisfy a parabolic equation that can be reduced to heat equation. Then it is proved that the mixed model is arbitrage-free. Finally, the capital of the model is presented as the limit of a sequence of semimartingales. 相似文献
17.
18.
In this paper we prove infinite dimensionality of some local and global cohomology groups on abstract Cauchy–Riemann manifolds. 相似文献
19.
Z. Wang 《Acta Mathematica Hungarica》2018,154(1):223-230
We generalize [4, Theorem 4.3] to the case of Hopf–Galois extension, by introducing the cotensor product of a comodule algebra and its opposite algebra, and then give some applications. 相似文献
20.
We study conditions under which sub-complexes of a double complex of vector spaces allow to compute the Bott–Chern cohomology. We are especially aimed at studying the Bott–Chern cohomology of special classes of solvmanifolds, namely, complex parallelizable solvmanifolds and solvmanifolds of splitting type. More precisely, we can construct explicit finite-dimensional double complexes that allow to compute the Bott–Chern cohomology of compact quotients of complex Lie groups, respectively, of some Lie groups of the type \(\mathbb {C}^n\ltimes _\varphi N\) where N is nilpotent. As an application, we compute the Bott–Chern cohomology of the complex parallelizable Nakamura manifold and of the completely solvable Nakamura manifold. In particular, the latter shows that the property of satisfying the \(\partial \overline{\partial }\)-Lemma is not strongly closed under deformations of the complex structure. 相似文献