DBpedia – Linked Data Fragments

Matches in DBpedia 2015-10 for { ?s ?p "In differential geometry, a Hodge cycle or Hodge class is a particular kind of homology class defined on a complex algebraic variety V, or more generally on a Kaehler manifold. A homology class x in a homology groupHk(V, C) = Hwhere V is a non-singular complex algebraic variety or Kaehler manifold is a Hodge cycle, provided it satisfies two conditions. Firstly, k is an even integer 2p, and in the direct sum decomposition of H shown to exist in Hodge theory, x is purely of type (p,p). Secondly, x is a rational class, in the sense that it lies in the image of the abelian group homomorphismHk(V, Q) → Hdefined in algebraic topology (as a special case of the universal coefficient theorem). The conventional term Hodge cycle therefore is slightly inaccurate, in that x is considered as a class (modulo boundaries); but this is normal usage.The importance of Hodge cycles lies primarily in the Hodge conjecture, to the effect that Hodge cycles should always be algebraic cycles, for V a complete algebraic variety. This is an unsolved problem, as of 2015; it is known that being a Hodge cycle is a necessary condition to be an algebraic cycle that is rational, and numerous particular cases of the conjecture are known."@en }

• Hodge_cycle abstract "In differential geometry, a Hodge cycle or Hodge class is a particular kind of homology class defined on a complex algebraic variety V, or more generally on a Kaehler manifold. A homology class x in a homology groupHk(V, C) = Hwhere V is a non-singular complex algebraic variety or Kaehler manifold is a Hodge cycle, provided it satisfies two conditions. Firstly, k is an even integer 2p, and in the direct sum decomposition of H shown to exist in Hodge theory, x is purely of type (p,p). Secondly, x is a rational class, in the sense that it lies in the image of the abelian group homomorphismHk(V, Q) → Hdefined in algebraic topology (as a special case of the universal coefficient theorem). The conventional term Hodge cycle therefore is slightly inaccurate, in that x is considered as a class (modulo boundaries); but this is normal usage.The importance of Hodge cycles lies primarily in the Hodge conjecture, to the effect that Hodge cycles should always be algebraic cycles, for V a complete algebraic variety. This is an unsolved problem, as of 2015; it is known that being a Hodge cycle is a necessary condition to be an algebraic cycle that is rational, and numerous particular cases of the conjecture are known.".