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On a problem in effective knot theory

Stefano Galatolo (1998)

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti Lincei. Matematica e Applicazioni

The following problem is investigated: «Find an elementary function F n : Z Z such that if Γ is a knot diagram with n crossings and the corresponding knot is trivial, then there is a sequence of Reidemeister moves that proves triviality such that at each step we have less than F n crossings». The problem is shown to be equivalent to a problem posed by D. Welsh in [7] and solved by geometrical techniques (normal surfaces).

On a secondary invariant of the hyperelliptic mapping class group

Takayuki Morifuji (2009)

Banach Center Publications

We discuss relations among several invariants of 3-manifolds including Meyer's function, the η-invariant, the von Neumann ρ-invariant and the Casson invariant from the viewpoint of the mapping class group of a surface.

On bilinear biquandles

Sam Nelson, Jacquelyn L. Rische (2008)

Colloquium Mathematicae

We define a type of biquandle which is a generalization of symplectic quandles. We use the extra structure of these bilinear biquandles to define new knot and link invariants and give some examples.

On boundary slopes of immersed incompressible surfaces

Mark D. Baker (1996)

Annales de l'institut Fourier

Let M be a compact, orientable, irreducible 3-manifold with M a torus. We show that there can be infinitely many slopes on M realized by the boundary curves of immersed, incompressible, - incompressible surfaces in M which are embedded in a neighborhood of M .

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