5 papers
Generalized torsion and Dehn filling
Tetsuya Ito, Kimihiko Motegi, Masakazu Teragaito
A generalized torsion element is a non-trivial element such that some non-empty finite product of its conjugates is the identity. We construct a generalized torsion element of the…
Twist left-veering open books, overtwistedness, looseness and virtual looseness
Tetsuya Ito, Keiko Kawamuro
We introduce twist left-veering mapping classes of punctured surfaces. We prove that a twist left-veering open book supports an overtwisted contact structure and determine when the…
Generalized torsion and decomposition of 3-manifolds
Tetsuya Ito, Kimihiko Motegi, Masakazu Teragaito
A nontrivial element in a group is a generalized torsion element if some nonempty finite product of its conjugates is the identity. We prove that any generalized torsion element in…
Positivities of knots and links and the defect of Bennequin inequality
Jesse Hamer, Tetsuya Ito, Keiko Kawamuro
We discuss relations among various positivities of knots and links, such as strong quasipositivity and quasipositivity. We give several pieces of supporting evidence for conjectura…
On the fractional Dehn twist coefficients of branched coverings
Tetsuya Ito, Keiko Kawamuro
We discuss how the fractional Dehn twist coefficient behaves under a fully ramified branched covering of an open book, and give applications to both topological and contact 3-manif…