Homological category weights and estimates for cat1(X,ξ)
نویسندگان
چکیده
منابع مشابه
Homological category weights and estimates for cat 1 ( X , ξ )
In this paper we study a new notion of category weight of homology classes developing further the ideas of E. Fadell and S. Husseini [3]. In the case of closed smooth manifolds the homological category weight is equivalent to the cohomological category weight of E. Fadell and S. Husseini but these two notions are distinct already for Poincaré complexes. An important advantage of the homological...
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In the first part of this paper the projective dimension of the structural modules in the BGG category O is studied. This dimension is computed for simple, standard and costandard modules. For tilting and injective modules an explicit conjecture relating the result to Lusztig’s a-function is formulated (and proved for type A). The second part deals with the extension algebra of Verma modules. I...
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In multi-attribute decision problems the decision to differentiate between alternatives will be affected by the precision with which weights are specified. Specifications are imprecise because of the uncertainty characteristic of the judgements on which weights are based. Uncertainties are from two sources, the accuracy with which judgements are articulated and the inconsistency when multiple j...
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We show, in full generality, that Lusztig’s a-function describes the projective dimension of both indecomposable tilting modules and indecomposable injective modules in the regular block of the BGG category O, proving a conjecture from the first paper. On the way we show that the images of simple modules under projective functors can be represented in the derived category by linear complexes of...
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We study homological algebra in the abelian category Γ̃, whose objects are functors from finite pointed sets to vector spaces over Fp. The full calculation of Tor ∗ -groups between functors of degree not exceeding p is presented. We compare our calculations with known results on homology of symmetric groups, Steenrod algebra and functor homology computations in the abelian category F of functors...
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ژورنال
عنوان ژورنال: Journal of the European Mathematical Society
سال: 2008
ISSN: 1435-9855
DOI: 10.4171/jems/110