Donaldson's theorem, Heegaard Floer homology, and knots with unknotting number one

Autor: Joshua Evan Greene
Rok vydání: 2014
Předmět:
Zdroj: Advances in Mathematics. 255:672-705
ISSN: 0001-8708
DOI: 10.1016/j.aim.2014.01.018
Popis: We establish an obstruction to unknotting an alternating knot by a single crossing change. The obstruction is lattice-theoretic in nature, and combines Donaldson's diagonalization theorem with an obstruction developed by Ozsvath and Szabo using Heegaard Floer homology. As an application, we enumerate the alternating 3-braid knots with unknotting number one, and show that each has an unknotting crossing in its standard alternating diagram.
Databáze: OpenAIRE