Published Paper
Inserted: 19 aug 2020
Last Updated: 10 jan 2022
Journal: Bulletin of the London Mathematical Society
Volume: 53
Number: 4
Pages: 1072-1092
Year: 2020
Doi: 10.1112/blms.12485
Abstract:
We prove some necessary conditions for a link to be: concordant to a quasi-positive link, quasi-positive, positive, or the closure of a positive braid. The main applications of our results are: a characterisation of positive links with unlinking number 1 and 2, and a combinatorial criterion to test if a positive link is the closure of a positive braid.