منابع مشابه
Witt Groups of Grassmann Varieties
We compute the total Witt groups of (split) Grassmann varieties, over any regular base X. The answer is a free module over the total Witt ring of X. We provide an explicit basis for this free module, which is indexed by a special class of Young diagrams, that we call even Young diagrams.
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For integers m ≥ p ≥ 2, let GR = GR(m,m + p) ⊂ RP N be the Plücker embedding of the Grassmannian of m-subspaces in Rm+p . We consider a central projection of GR into a projective space RP mp of the same dimension as GR . Although GR may be non-orientable, the topological degree of this projection can be properly defined. Its values are unsigned integers. It turns out that when mp is even, the d...
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Following Weyl’s account in The Classical Groups we develop an analogue of the (first and second) Fundamental Theorems of Invariant Theory for rings of differential operators: when V is a k-dimensional complex vector space with the standard SLkC action, we give a presentation of the ring of invariant differential operators D(C[V n])SLkC and a description of the ring of differential operators on...
متن کاملSchubert unions in Grassmann varieties
We study subsets of Grassmann varieties G(l, m) over a field F , such that these subsets are unions of Schubert cycles, with respect to a fixed flag. We study the linear spans of, and in case of positive characteristic, the number of Fq-rational points on such unions. Moreover we study a geometric duality of such unions, and give a combinatorial interpretation of this duality. We discuss the ma...
متن کاملAutomorphism groups of Grassmann codes
Article history: Received 9 May 2012 Revised 17 February 2013 Accepted 30 April 2013 Available online 14 May 2013 Communicated by Xiang-dong Hou MSC: 14M15 20B25 94B05 94B27
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ژورنال
عنوان ژورنال: Journal of Algebraic Geometry
سال: 2012
ISSN: 1056-3911,1534-7486
DOI: 10.1090/s1056-3911-2012-00613-4