## Geometry & Topology

### Computations of the Ozsváth–Szabó knot concordance invariant

Charles Livingston

#### Abstract

Ozsváth and Szabó have defined a knot concordance invariant $τ$ that bounds the 4–ball genus of a knot. Here we discuss shortcuts to its computation. We include examples of Alexander polynomial one knots for which the invariant is nontrivial, including all iterated untwisted positive doubles of knots with nonnegative Thurston–Bennequin number, such as the trefoil, and explicit computations for several 10 crossing knots. We also note that a new proof of the Slice–Bennequin Inequality quickly follows from these techniques.

#### Article information

Source
Geom. Topol., Volume 8, Number 2 (2004), 735-742.

Dates
Accepted: 29 April 2004
First available in Project Euclid: 21 December 2017

https://projecteuclid.org/euclid.gt/1513883415

Digital Object Identifier
doi:10.2140/gt.2004.8.735

Mathematical Reviews number (MathSciNet)
MR2057779

Zentralblatt MATH identifier
1067.57008

#### Citation

Livingston, Charles. Computations of the Ozsváth–Szabó knot concordance invariant. Geom. Topol. 8 (2004), no. 2, 735--742. doi:10.2140/gt.2004.8.735. https://projecteuclid.org/euclid.gt/1513883415

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