1,818 research outputs found
Simply connected projective manifolds in characteristic have no nontrivial stratified bundles
We show that simply connected projective manifolds in characteristic
have no nontrivial stratified bundles. This gives a positive answer to a
conjecture by D. Gieseker. The proof uses Hrushovski's theorem on periodic
points.Comment: 16 pages. Revised version contains a more general theorem on torsion
points on moduli, together with an illustration in rank 2 due to M. Raynaud.
Reference added. Last version has some typos corrected. Appears in
Invent.math
Eliashberg's proof of Cerf's theorem
Following a line of reasoning suggested by Eliashberg, we prove Cerf's
theorem that any diffeomorphism of the 3-sphere extends over the 4-ball. To
this end we develop a moduli-theoretic version of Eliashberg's
filling-with-holomorphic-discs method.Comment: 32 page
Measuring the functionality of online stores
This paper makes a case for the need of a framework which can be used to measure the functionality delivered by electronic commerce (e-commerce) systems. Such a framework would be helpful in areas such as cost prediction, effort estimatation, and so on. The paper also goes on to propose such a framework, based on the tried and tested methods of function points and object points.peer-reviewe
Large N 2D Yang-Mills Theory and Topological String Theory
We describe a topological string theory which reproduces many aspects of the
1/N expansion of SU(N) Yang-Mills theory in two spacetime dimensions in the
zero coupling (A=0) limit. The string theory is a modified version of
topological gravity coupled to a topological sigma model with spacetime as
target. The derivation of the string theory relies on a new interpretation of
Gross and Taylor's ``\Omega^{-1} points.'' We describe how inclusion of the
area, coupling of chiral sectors, and Wilson loop expectation values can be
incorporated in the topological string approach.Comment: 95 pages, 15 Postscript figures, uses harvmac (Please use the "large"
print option.) Extensive revisions of the sections on topological field
theory. Added a compact synopsis of topological field theory. Minor typos
corrected. References adde
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