Baer-invariants, isologism, varietal laws and homology
نویسندگان
چکیده
منابع مشابه
Baer Invariants in Semi-abelian Categories Ii: Homology
This article treats the problem of deriving the reflector of a semi-abelian category A onto a Birkhoff subcategory B of A. Basing ourselves on Carrasco, Cegarra and Grandjeán’s homology theory for crossed modules, we establish a connection between our theory of Baer invariants with a generalization—to semi-abelian categories— of Barr and Beck’s cotriple homology theory. This results in a semi-a...
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By using surgery techniques, we compute Floer homology for certain classes of integral homology 3-spheres homology cobordant to zero. We prove that Floer homology is two-periodic for all these manifolds. Based on this fact, we introduce a new integer valued invariant of integral homology 3-spheres. Our computations suggest its homology cobordism invariance.
متن کاملBaer Invariants in Semi-abelian Categories I: General Theory
Extending the work of Fröhlich, Lue and Furtado-Coelho, we consider the theory of Baer invariants in the context of semi-abelian categories. Several exact sequences, relative to a subfunctor of the identity functor, are obtained. We consider a notion of commutator which, in the case of abelianization, corresponds to Smith’s. The resulting notion of centrality fits into Janelidze and Kelly’s the...
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We introduce topological invariants of knots and braid conjugacy classes, in the form of differential graded algebras, and present an explicit combinatorial formulation for these invariants. The algebras conjecturally give the relative contact homology of certain Legendrian tori in fivedimensional contact manifolds. We present several computations and derive a relation between the knot invarian...
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In this paper we define and investigate Z2–homology cobordism invariants of Z2–homology 3–spheres which turn out to be related to classical invariants of knots. As an application we show that many lens spaces have infinite order in the Z2–homology cobordism group and we prove a lower bound for the slice genus of a knot on which integral surgery yields a given Z2– homology sphere. We also give s...
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ژورنال
عنوان ژورنال: Acta Mathematica
سال: 1976
ISSN: 0001-5962
DOI: 10.1007/bf02392415