1,279 research outputs found
New evidence for Green's conjecture on syzygies of canonical curves
We prove that two weakened forms of Green's conjectures for canonical curves
are equivalent when the genus is odd.Comment: Tex-type: LaTe
Projective normality of flag varieties and Schubert varieties
This article does not have an abstract
Some remarks on the instability flag
This article does not have an abstract
Local Projections of Low-Momentum Potentials
Nuclear interactions evolved via renormalization group methods to lower
resolution become increasingly non-local (off-diagonal in coordinate space) as
they are softened. This inhibits both the development of intuition about the
interactions and their use with some methods for solving the quantum many-body
problem. By applying "local projections", a softened interaction can be reduced
to a local effective interaction plus a non-local residual interaction. At the
two-body level, a local projection after similarity renormalization group (SRG)
evolution manifests the elimination of short-range repulsive cores and the flow
toward universal low-momentum interactions. The SRG residual interaction is
found to be relatively weak at low energy, which motivates a perturbative
treatment
On semistable principal bundles over a complex projective manifold, II
Let (X, \omega) be a compact connected Kaehler manifold of complex dimension
d and E_G a holomorphic principal G-bundle on X, where G is a connected
reductive linear algebraic group defined over C. Let Z (G) denote the center of
G. We prove that the following three statements are equivalent: (1) There is a
parabolic subgroup P of G and a holomorphic reduction of the structure group of
E_G to P (say, E_P) such that the bundle obtained by extending the structure
group of E_P to L(P)/Z(G) (where L(P) is the Levi quotient of P) admits a flat
connection; (2) The adjoint vector bundle ad(E_G) is numerically flat; (3) The
principal G-bundle E_G is pseudostable, and the degree of the charateristic
class c_2(ad(E_G) is zero.Comment: 15 page
Downlink scheduling in CDMA data networks
We identify optimality properties for scheduling downlink transmissions to data users in CDMA networks. For arbitrary-topology networks, we show that under certain idealizing assumptions it is optimal for a base station to transmit to only one data user at a time. Moreover, for data-only networks, we prove that a base station, when on, should transmit at maximum power for optimality. We use these two properties to obtain a mathematical programming formulation for determining the optimal transmission schedule in linear data-only networks, with time allocations playing the role of decision variables. The optimality conditions imply that there exist (i) subsets of outer users on either side of the cell that should be served when only the neighboring base station on the opposite side is on; (ii) a subset of inner users in the center of the cell that should be served when both neighbors are on; (iii) a subset of users in the intermediate regions that should receive transmissions when both neighbors are off. Exploiting these structural properties, we derive a simple search algorithm for finding the optimal transmission schedule in symmetric scenarios. Numerical experiments illustrate that scheduling achieves significant capacity gains over conventional CDMA
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