Enrico Manfredi - Academia.edu (original) (raw)
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Papers by Enrico Manfredi
Analele Universitatii "Ovidius" Constanta - Seria Matematica, 2012
We introduce the concept of regular diagrams for knots and links in lens spaces, proving that two... more We introduce the concept of regular diagrams for knots and links in lens spaces, proving that two diagrams represent equivalent links if and only if they are related by a finite sequence of seven Reidemester type moves. As a particular case, we obtain diagrams and moves for links in RP 3 previously introduced by Y.V. Drobothukina.
Topology and its Applications, 2013
In this paper we study some aspects of knots and links in lens spaces. Namely, if we consider len... more In this paper we study some aspects of knots and links in lens spaces. Namely, if we consider lens spaces as quotient of the unit ball B 3 with suitable identification of boundary points, then we can project the links on the equatorial disk of B 3 , obtaining a regular diagram for them. In this contest, we obtain a complete finite set of Reidemeister type moves establishing equivalence, up to ambient isotopy, a Wirtinger type presentation for the fundamental group of the complement of the link and a diagrammatic method giving the first homology group. We also compute Alexander polynomial and twisted Alexander polynomials of this class of links, showing their correlation with Reidemeister torsion.
Analele Universitatii "Ovidius" Constanta - Seria Matematica, 2012
We introduce the concept of regular diagrams for knots and links in lens spaces, proving that two... more We introduce the concept of regular diagrams for knots and links in lens spaces, proving that two diagrams represent equivalent links if and only if they are related by a finite sequence of seven Reidemester type moves. As a particular case, we obtain diagrams and moves for links in RP 3 previously introduced by Y.V. Drobothukina.
Topology and its Applications, 2013
In this paper we study some aspects of knots and links in lens spaces. Namely, if we consider len... more In this paper we study some aspects of knots and links in lens spaces. Namely, if we consider lens spaces as quotient of the unit ball B 3 with suitable identification of boundary points, then we can project the links on the equatorial disk of B 3 , obtaining a regular diagram for them. In this contest, we obtain a complete finite set of Reidemeister type moves establishing equivalence, up to ambient isotopy, a Wirtinger type presentation for the fundamental group of the complement of the link and a diagrammatic method giving the first homology group. We also compute Alexander polynomial and twisted Alexander polynomials of this class of links, showing their correlation with Reidemeister torsion.