1,488 research outputs found
Random Walks and Market Efficiency: Evidence from International Real Estate Markets
This study performs tests of the random walk hypothesis for international commercial real estate markets utilizing stock market indices of real estate share prices for three geographical regions: Europe, Asia and North America. The augmented Dickey-Fuller and Phillips-Perron unit root tests and Cochrane variance ratio test find that each of these markets (as well as associated broader stock markets) exhibits random walk behavior. Moreover, a non-parametric runs test provides support for weak-form market efficiency in the real estate markets. In addition, Johansen-Juselius co-integration analysis reveals that all three markets appear co-integrated and share a common long-run stochastic trend. Results of co-integration analyses and vector error correction models suggest that diversification benefits through international real estate securities can only be achieved in the short run.
Inclusion-exclusion and Segre classes
We propose a variation of the notion of Segre class, by forcing a naive
`inclusion-exclusion' principle to hold. The resulting class is computationally
tractable, and is closely related to Chern-Schwartz-MacPherson classes. We
deduce several general properties of the new class from this relation, and
obtain an expression for the Milnor class of a scheme in terms of this class.Comment: 8 page
A short proof of the G\"ottsche conjecture
We prove that for a sufficiently ample line bundle on a surface , the
number of -nodal curves in a general -dimensional linear system
is given by a universal polynomial of degree in the four numbers
and .
The technique is a study of Hilbert schemes of points on curves on a surface,
using the BPS calculus of [PT3] and the computation of tautological integrals
on Hilbert schemes by Ellingsrud, G\"ottsche and Lehn.
We are also able to weaken the ampleness required, from G\"ottsche's
-very ample to -very ample.Comment: 8 pages. Published versio
Theory of Neutron Diffraction from the Vortex Lattice in UPt3
Neutron scattering experiments have recently been performed in the
superconducting state of UPt3 to determine the structure of the vortex lattice.
The data show anomalous field dependence of the aspect ratio of the unit cell
in the B phase. There is apparently also a change in the effective coherence
length on the transition from the B to the C phases. Such observations are not
consistent with conventional superconductvity. A theory of these results is
constructed based on a picture of two-component superconductivity for UPt3. In
this way, these unusual observations can be understood. There is a possible
discrepancy between theory and experiment in the detailed field dependence of
the aspect ratio.Comment: 11 pages; uses REVTEX, APS and PRABIB styles; 2 Postscript figure
files include
Material Support: Counternarcotics vs. Counterinsurgency in Afghanistan
Microeconomic analysis of counternarcotics strategies in Afghanistan suggests that current policies lend material support to the enemy. Vigorous enforcement can increase the flow of funds to insurgents and other parties that profit from trafficking. Rural-development programs, promoted as elements of a counternarcotics strategy, are open to some of the same objections. The benefits of drug-fighting in Afghanistan for consumer countries in Europe and North America are likely to be modest. Anti-corruption efforts in Afghanistan and demand-reduction programs both in Afghanistan and in consumer countries, insofar as they are feasible, could serve both counternarcotics and counterinsurgency objectives
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