990 research outputs found
Codimensions of root valuation strata
This paper defines and studies a stratification of the adjoint quotient of
the Lie algebra of a reductive group over a Laurent power series field. The
stratification arises naturally in the context of affine Springer fibers
The Boden-Hu conjecture holds precisely up to rank eight
Consider moduli schemes of vector bundles over a smooth projective curve
endowed with parabolic structures over a marked point. Boden and Hu observed
that a slight variation of the weights leads to a desingularisation of the
moduli scheme, and they conjectured that one can always obtain a small
resolution this way. The present text proves this conjecture in some cases
(including all bundles of rank up to eight) and gives counterexamples in all
other cases (in particular in every rank beyond eight). The main tool is a
generalisation of Ext-groups involving more than two quasiparabolic bundles.Comment: 17 page
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