a special type of 2 component link complement - MathOverflow most recent 30 from http://mathoverflow.net 2013-05-19T04:53:22Z http://mathoverflow.net/feeds/question/82451 http://www.creativecommons.org/licenses/by-nc/2.5/rdf http://mathoverflow.net/questions/82451/a-special-type-of-2-component-link-complement a special type of 2 component link complement Bin Yu 2011-12-02T13:14:01Z 2011-12-02T14:19:14Z <p>It is well know that a 2 component link complement may doesn't detect the link type. My question is <strong>whether the following type of 2 component links detect their link types?</strong></p> <p><strong>Such a link is composed of a knot with its meridian circle.</strong> Here its meridian circle means a meridian of the boundary of a solid torus neighborhood of the knot. Thank you.</p> http://mathoverflow.net/questions/82451/a-special-type-of-2-component-link-complement/82460#82460 Answer by Bruno Martelli for a special type of 2 component link complement Bruno Martelli 2011-12-02T14:19:14Z 2011-12-02T14:19:14Z <p>I suppose that you are asking whether such links are determined by their complement. If this is the case, the answer is yes and it is a consequence of Gordon-Luecke's "knots are determinent by their complement" theorem. </p> <p>The technique of a proof goes as follows. Since now "the complement of" means "the complement of an open tubolar neighborhood of". Let $K$ be a knot and $m$ an encircling meridian. We want to prove that $K\cup m$ is the only 2-component link having its complement. Gordon-Luecke says that the complement of $K$ is a compact manifold $M$ with one torus boundary, which has only one slope $s$ whose Dehn filling gives $S^3$. </p> <p>The complement of $K\cup m$ is homeomorphic to the union $N=M\cup(P\times S^1)$ of $M$ and one copy of $P\times S^1$ where $P$ is the pair-of-pants. The fiber of $P\times S^1$ is glued to $M$ along the slope $s$. As usual with link complements, the problem of finding links in $S^3$ whose complement is $N$ translates into studying the Dehn fillings of $N$ giving $S^3$. By Gordon-Luecke, the only way to get $S^3$ is that $P\times S^1$ transforms into a solid torus with meridian $s$. One studies and easily classifies the fillings of $P\times S^1$ giving a solid torus with fiber-parallel meridian, and see that they all give rise to the same link.</p>