116 research outputs found
Topological properties of punctual Hilbert schemes of almost-complex fourfolds (I)
In this article, we study topological properties of Voisin's punctual Hilbert
schemes of an almost-complex fourfold . In this setting, we compute their
Betti numbers and construct Nakajima operators. We also define tautological
bundles associated with any complex bundle on , which are shown to be
canonical in -theory
Fiducial Reference Measurements for Validation of Surface Temperature from Satellites (FRM4STS) - A Framework to Verify the Field Performance of TIR FRM
Google Earth Engine Open-Source Code for Land Surface Temperature Estimation from the Landsat Series
Land Surface Temperature (LST) is increasingly important for various studies assessing land surface conditions, e.g., studies of urban climate, evapotranspiration, and vegetation stress. The Landsat series of satellites have the potential to provide LST estimates at a high spatial resolution, which is particularly appropriate for local or small-scale studies. Numerous studies have proposed LST retrieval algorithms for the Landsat series, and some datasets are available online. However, those datasets generally require the users to be able to handle large volumes of data. Google Earth Engine (GEE) is an online platform created to allow remote sensing users to easily perform big data analyses without increasing the demand for local computing resources. However, high spatial resolution LST datasets are currently not available in GEE. Here we provide a code repository that allows computing LSTs from Landsat 4, 5, 7, and 8 within GEE. The code may be used freely by users for computing Landsat LST as part of any analysis within GEE
Topological quantum field theory and four-manifolds
I review some recent results on four-manifold invariants which have been
obtained in the context of topological quantum field theory. I focus on three
different aspects: (a) the computation of correlation functions, which give
explicit results for the Donaldson invariants of non-simply connected
manifolds, and for generalizations of these invariants to the gauge group
SU(N); (b) compactifications to lower dimensions, and relations with
three-manifold topology and with intersection theory on the moduli space of
flat connections on Riemann surfaces; (c) four-dimensional theories with
critical behavior, which give some remarkable constraints on Seiberg-Witten
invariants and new results on the geography of four-manifolds.Comment: 10 pages, LaTeX. Talk given at the 3rd ECM, Barcelona, July 2000;
references adde
Vertex Operators, Grassmannians, and Hilbert Schemes
We describe a well-known collection of vertex operators on the infinite wedge
representation as a limit of geometric correspondences on the equivariant
cohomology groups of a finite-dimensional approximation of the Sato
grassmannian, by cutoffs in high and low degrees. We prove that locality, the
boson-fermion correspondence, and intertwining relations with the Virasoro
algebra are limits of the localization expression for the composition of these
operators. We then show that these operators are, almost by definition, the
Hilbert scheme vertex operators defined by Okounkov and the author in \cite{CO}
when the surface is with the torus action .Comment: 20 pages, 0 figure
An Approach to ADE Gauge Theory on K3
We propose a recipe for determination of the partition function of gauge theory on by generalizing our previous results of the
SU(N) case. The resulting partition function satisfies Montonen-Olive duality
for gauge group.Comment: 28 pages, Latex, enlarged published versio
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