159 research outputs found
The L^2 signature of torus knots
We find a formula for the L2 signature of a (p,q) torus knot, which is the
integral of the omega-signatures over the unit circle. We then apply this to a
theorem of Cochran-Orr-Teichner to prove that the n-twisted doubles of the
unknot, for n not 0 or 2, are not slice. This is a new proof of the result
first proved by Casson and Gordon.Comment: 11 pages, Version 2 contains a note explaining that the main theorem
of the paper has already been proved in earlier work by Kirby and Melvi
Open book decompositions for contact structures on Brieskorn manifolds
In this paper, we give an open book decomposition for the contact structures
on some Brieskorn manifolds, in particular for the contact structures of
Ustilovsky. The decomposition uses right-handed Dehn twists as conjectured by
Giroux.Comment: 6 pages, no figure
Scissor equivalence for torus links
This article is about a natural distance function induced by smooth
cobordisms between links. We show that the cobordism distance of torus links is
determined by the profiles of their signature functions, up to a constant
factor.Comment: 15 pages, 5 figures, Theorem 1 adde
Highly connected manifolds with positive Ricci curvature
We prove the existence of Sasakian metrics with positive Ricci curvature on
certain highly connected odd dimensional manifolds. In particular, we show that
manifolds homeomorphic to the 2k-fold connected sum of S^{2n-1} x S^{2n} admit
Sasakian metrics with positive Ricci curvature for all k. Furthermore, a
formula for computing the diffeomorphism types is given and tables are
presented for dimensions 7 and 11.Comment: This is the version published by Geometry & Topology on 29 November
200
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