9,800,368 research outputs found
Andreas Wimmer, Lars-Erik Cederman, and Brian Min Ethnic politics and armed conflict. A configurational analysis of a new global dataset. Published in the American Sociological Review 74(2), 2009 ONLINE APPENDIX
The Ethnic Power Relations (EPR) data set improves on earlier work along similar line
Proposals for additional INSET days: consultation on future requirements for additional INSET days
"This consultation is designed to gather views on the Welsh Assembly Government’s proposals for additional INSET days in the school year 2010/11, in order to inform decisions for this school year and consideration of longer-term requirements. Additional INSET days are ‘additional’ to the five statutory non-teaching days available to schools." - overview
Siegel's lemma with additional conditions
Let be a number field, and let be a subspace of , .
Let be subspaces of of dimension less than dimension of
. We prove the existence of a point of small height in , providing an explicit upper bound on the height of such a
point in terms of heights of and . Our main tool is a counting
estimate we prove for the number of points of a subspace of inside of an
adelic cube. As corollaries to our main result we derive an explicit bound on
the height of a non-vanishing point for a decomposable form and an effective
subspace extension lemma.Comment: 12 pages, revised version, to appear in Journal of Number Theor
Leptogenesis from Additional Higgs Doublets
Leptogenesis may be induced by the mixing of extra Higgs doublets with
experimentally accessible masses. This mechanism relies on diagrammatic cuts
that are kinematically forbidden in the vacuum but contribute at finite
temperature. A resonant enhancement of the asymmetry occurs generically
provided the dimensionless Yukawa and self-interactions are suppressed compared
to those of the Standard Model Higgs field. This is in contrast to typical
scenarios of Resonant Leptogenesis, where the asymmetry is enhanced by imposing
a degeneracy of singlet neutrino masses.Comment: 12 pages; more phenomenological details adde
-zips with additional structure
An -zip over a scheme over a finite field is a certain object of
semi-linear algebra consisting of a locally free module with a descending
filtration and an ascending filtration and a \Frob_q-twisted isomorphism
between the respective graded sheaves. In this article we define and
systematically investigate what might be called "-zips with a
-structure", for an arbitrary reductive linear algebraic group .
These objects come in two incarnations. One incarnation is an exact linear
tensor functor from the category of finite dimensional representations of
to the category of -zips over . Locally any such functor has a type
, which is a cocharacter of . The other incarnation is a certain
-torsor analogue of the notion of -zips. We prove that both incarnations
define stacks that are naturally equivalent to a quotient stack of the form
that was studied in an earlier paper. By the
results obtained there they are therefore smooth algebraic stacks of dimension
0 over . Using our earlier results we can also classify the isomorphism
classes of such objects over an algebraically closed field, describe their
automorphism groups, and determine which isomorphism classes can degenerate
into which others.
For classical groups we can deduce the corresponding results for twisted or
untwisted symplectic, orthogonal, or unitary -zips. The results can be
applied to the algebraic de Rham cohomology of smooth projective varieties (or
generalizations thereof such as smooth proper Deligne-Mumford stacks) and to
truncated Barsotti-Tate groups of level 1. In addition, we hope that our
systematic group theoretical approach will help to understand the analogue of
the Ekedahl-Oort stratification of the special fibers of arbitrary Shimura
varieties.Comment: Remark 9.20 explained, otherwise minor changes and corrections; final
version, to appear in Pacific Journal of Math.; 50 page
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