Embeddings
Mostrando 13-17 de 17 artigos, teses e dissertações.
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13. Some isometric embedding and rigidity results for Riemannian manifolds
In this note, we announce some new results concerning rigidity and isometric embeddings of Riemannian manifolds. A special case of the main result states that a general Mn [unk] Rn+r, r≤(n - 1)(n - 2)/2, is uniquely determined up to finitely many constants by its induced ds2.
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14. Characteristic classes, singular embeddings, and intersection homology
This note announces some results on the relationship between global invariants and local topological structure. The first section gives a local-global formula for Pontrjagin classes or L-classes. The second section describes a corresponding decomposition theorem on the level of complexes of sheaves. A final section mentions some related aspects of “singula
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15. Collinearity-preserving functions between Desarguesian planes
Using concepts from valuation theory, we obtain a characterization of all collinearity-preserving functions from one affine or projective Desarguesian plane into another. The case in which the planes are projective and the range contains a quadrangle has been treated previously in the literature. Our results permit one or both planes to be affine and include
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16. Existence of simply connected algebraic surfaces of general type with positive and zero indices
In the classification problem of algebraic surfaces of general type, an important conjecture states that for simply connected such surfaces Chern numbers satisfy the inequality c12 ≤ 2c2 (or equivalently, the index τ ≤ 0). We disprove this conjecture by computing fundamental groups of Galois coverings corresponding to generic CP2 projections of projecti
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17. Algebraic aspects of the computably enumerable degrees.
A set A of nonnegative integers is computably enumerable (c.e.), also called recursively enumerable (r.e.), if there is a computable method to list its elements. The class of sets B which contain the same information as A under Turing computability (