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991.
We construct a new order 1 invariant for knot diagrams. We use it to determine the minimal number of Reidemeister moves needed
to pass between certain pairs of knot diagrams.
J. Hass was partially supported by an NSF grant. 相似文献
992.
Sönke Rollenske 《Mathematische Annalen》2008,341(3):623-628
The Frölicher spectral sequence of a compact complex manifold X measures the difference between Dolbeault cohomology and de Rham cohomology. If X is Kähler then the spectral sequence collapses at the E 1term and no example with d n ≠ 0 for n > 3 has been described in the literature.We construct for n ≥ 2 nilmanifolds with left-invariant complex structure X n such that the n-th differential d n does not vanish. This answers a question mentioned in the book of Griffiths and Harris. 相似文献
993.
Joonil Kim 《Mathematische Zeitschrift》2008,258(2):271-290
Let {X
j
, Y
j
, T : 1 ≤ j ≤ n} be a basis satisfying the commutation relation for the Heisenberg Lie algebra . Then we obtain a multi-parameter Marcinkiewicz multiplier theorem for the operator defined by m(X
1,..., X
n
, Y
1,..., Y
n
, T). 相似文献
994.
In (Kaniuth and Kumar in Math. Proc. Camb. Phil. Soc. 131, 487–494, 2001) Hardy’s uncertainty principle for was generalized to connected and simply connected nilpotent Lie groups. In this paper, we extend it further to connected
nilpotent Lie groups with non-compact centre. Concerning the converse, we show that Hardy’s theorem fails for a connected
nilpotent Lie group G which admits a square integrable irreducible representation and that this condition is necessary if the simply connected
covering group of G satisfies the flat orbit condition. 相似文献
995.
Marta Pérez Rodríguez 《Journal of Pure and Applied Algebra》2008,212(11):2381-2388
We provide the main results of a deformation theory of smooth formal schemes as defined in [L. Alonso Tarrío, A. Jeremías López, M. Pérez Rodríguez, Infinitesimal lifting and Jacobi criterion for smoothness on formal schemes, Comm. Algebra 35 (2007) 1341-1367]. Smoothness is defined by the local existence of infinitesimal liftings. Our first result is the existence of an obstruction in a certain Ext1 group whose vanishing guarantees the existence of global liftings of morphisms. Next, given a smooth morphism f0:X0→Y0 of noetherian formal schemes and a closed immersion Y0?Y given by a square zero ideal I, we prove that the set of isomorphism classes of smooth formal schemes lifting X0 over Y is classified by and that there exists an element in which vanishes if and only if there exists a smooth formal scheme lifting X0 over Y. 相似文献
996.
Wolfgang Dahmen Thorsten Rohwedder Reinhold Schneider Andreas Zeiser 《Numerische Mathematik》2008,110(3):277-312
This paper is concerned with the design and analysis of a fully adaptive eigenvalue solver for linear symmetric operators.
After transforming the original problem into an equivalent one formulated on ℓ
2, the space of square summable sequences, the problem becomes sufficiently well conditioned so that a gradient type iteration
can be shown to reduce the error by some fixed factor per step. It then remains to realize these (ideal) iterations within
suitable dynamically updated error tolerances. It is shown under which circumstances the adaptive scheme exhibits in some
sense asymptotically optimal complexity.
This research was supported in part by the Leibniz Programme of the DFG, by the SFB 401 funded by DFG, the DFG Priority Program
SPP1145 and by the EU NEST project BigDFT. 相似文献
997.
We study estimates for proper orthogonal decomposition eigenvectors and eigenvalues as well as error estimates between the
exact solution of a 2D Navier–Stokes model and the numerical approach when the proper orthogonal decomposition method is considered.
These estimates are also extended when bifurcation diagram are calculated using the so called p-POD or SPOD methods with a
new cut-off criterion to minimize noisy modes produced by the p-POD method. 相似文献
998.
Tiziana Giorgi Robert Smits 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》2008,59(4):600-618
We consider the principal eigenvalue λ
1Ω(α) corresponding to Δu = λ (α) u in on ∂Ω, with α a fixed real, and a C
0,1 bounded domain. If α > 0 and small, we derive bounds for λ
1Ω(α) in terms of a Stekloff-type eigenvalue; while for α > 0 large we study the behavior of its growth in terms of maximum curvature.
We analyze how domain monotonicity of the principal eigenvalue depends on the geometry of the domain, and prove that domains
which exhibit domain monotonicity for every α are calibrable. We conjecture that a domain has the domain monotonicity property for some α if and only if it is calibrable.
Robert Smits: This author was partially supported by a grant of the National Security Agency, grant #H98230-05-1-0060. 相似文献
999.
James P. Lin 《Topology and its Applications》2008,156(2):420-432
Let X be a homotopy associative mod p H-space for p an odd prime. The homology H*(X;Fp) is an associative ring, but not necessarily commutative. We study conditions when for elements of H*(X;Fp). Under certain conditions imply for l=p−2 or p−1. These methods can be used to prove results about homology commutators that were previously obtained using the adjoint action [H. Hamanaka, S. Hara, A. Kono, Adjoint action of Lie groups on the loop spaces and cohomology of exceptional Lie groups, Transform. Group Theory (1996) 44-50, Korea Adv. Inst. Sci. Tech.; A. Kono, K. Kozima, The adjoint action of a Lie group on the space of loops, J. Math. Soc. Japan 45 (3) (1993) 495-509; A. Kono, J. Lin, O. Nishimura, Characterization of the mod 3 cohomology of E7, Proc. Amer. Math. Soc. 131 (10) (2003) 3289-3295]. We also generalize results of Kane [R. Kane, Torsion in homotopy associative H-spaces, Illinois J. Math. 20 (1976) 476-485] to nonfinite mod p homotopy associative H-spaces. 相似文献
1000.
P is the class of pseudocompact Hausdorff topological groups, and P′ is the class of groups which admit a topology T such that (G,T)∈P. It is known that every G=(G,T)∈P is totally bounded, so for G∈P′ the supremum T∨(G) of all pseudocompact group topologies on G and the supremum T#(G) of all totally bounded group topologies on G satisfy T∨⊆T#.The authors conjecture for abelian G∈P′ that T∨=T#. That equality is established here for abelian G∈P′ with any of these (overlapping) properties. (a) G is a torsion group; (b) |G|?c2; (c) r0(G)=|G|=ω|G|; (d) |G| is a strong limit cardinal, and r0(G)=|G|; (e) some topology T with (G,T)∈P satisfies w(G,T)?c; (f) some pseudocompact group topology on G is metrizable; (g) G admits a compact group topology, and r0(G)=|G|. Furthermore, the product of finitely many abelian G∈P′, each with the property T∨(G)=T#(G), has the same property. 相似文献