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In the mathematical theory of knots, a satellite knot is a knot that contains an incompressible, non boundary-parallel torus in its complement.〔Colin Adams, ''The Knot Book: An Elementary Introduction to the Mathematical Theory of Knots'', (2001), ISBN 0-7167-4219-5〕 Every knot is either hyperbolic, a torus, or a satellite knot. The class of satellite knots include composite knots, cable knots and Whitehead doubles. (''See'' Basic families, below for definitions of the last two classes.) A satellite ''link'' is one that orbits a companion knot ''K'' in the sense that it lies inside a regular neighborhood of the companion. A satellite knot can be picturesquely described as follows: start by taking a nontrivial knot lying inside an unknotted solid torus . Here "nontrivial" means that the knot is not allowed to sit inside of a 3-ball in and is not allowed to be isotopic to the central core curve of the solid torus. Then tie up the solid torus into a nontrivial knot. This means there is a non-trivial embedding and . The central core curve of the solid torus is sent to a knot , which is called the "companion knot" and is thought of as the planet around which the "satellite knot" orbits.The construction ensures that is a non-boundary parallel incompressible torus in the complement of . Composite knots contain a certain kind of incompressible torus called a swallow-follow torus, which can be visualized as swallowing one summand and following another summand. Since is an unknotted solid torus, is a tubular neighbourhood of an unknot . The 2-component link together with the embedding is called the ''pattern'' associated to the satellite operation. A convention: people usually demand that the embedding is ''untwisted'' in the sense that must send the standard longitude of to the standard longitude of . Said another way, given two disjoint curves , must preserve their linking numbers i.e.: . ==Basic families== When is a torus knot, then is called a ''cable knot.'' Examples 3 and 4 are cable knots. If is a non-trivial knot in and if a compressing disc for intersects in precisely one point, then is called a ''connect-sum.'' Another way to say this is that the pattern is the connect-sum of a non-trivial knot with a Hopf link. If the link is the Whitehead link, is called a ''Whitehead double.'' If is untwisted, is called an untwisted Whitehead double. 抄文引用元・出典: フリー百科事典『 ウィキペディア(Wikipedia)』 ■ウィキペディアで「satellite knot」の詳細全文を読む スポンサード リンク
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