Difference between revisions of "Knot table"
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− | The list of diagrams of all simple knots admitting a projection on the plane with 9 or fewer double points. The notation for the knots in this table is standard; the first number indicates the number of double points and the second (placed as a suffix) the ordinal number of the knot. E.g., the knot | + | {{TEX|done}} |
+ | The list of diagrams of all simple knots admitting a projection on the plane with 9 or fewer double points. The notation for the knots in this table is standard; the first number indicates the number of double points and the second (placed as a suffix) the ordinal number of the knot. E.g., the knot $7_5$ is the fifth knot in the table with 7 intersections. Alongside each knot in coded form is given its Alexander polynomial $\Delta(t)=a_{2n}t^{2n}+\ldots+a_nt^n+\ldots+a_0$ (cf. [[Alexander invariants|Alexander invariants]]). Since the Alexander polynomial of every knot has even degree and is reciprocal (i.e. $a_i=a_{2n-i}$), it suffices to give the set of last coefficients $a_n,\ldots,a_0$; they are indicated in the table. E.g., next to the knot $8_9$ is written $7-5+3-1$. This means that the Alexander polynomial equals $\Delta(t)=-t^6+3t^5-5t^4+7t^3-5t^2+3t-1$. Non-alternating knots are marked by an asterisk (cf. [[Alternating knots and links|Alternating knots and links]]). The table is taken from [[#References|[1]]] with minor modifications. | ||
<img style="border:1px solid;" src="https://www.encyclopediaofmath.org/legacyimages/common_img/k055590a.gif" /> | <img style="border:1px solid;" src="https://www.encyclopediaofmath.org/legacyimages/common_img/k055590a.gif" /> |
Revision as of 20:28, 11 April 2014
The list of diagrams of all simple knots admitting a projection on the plane with 9 or fewer double points. The notation for the knots in this table is standard; the first number indicates the number of double points and the second (placed as a suffix) the ordinal number of the knot. E.g., the knot $7_5$ is the fifth knot in the table with 7 intersections. Alongside each knot in coded form is given its Alexander polynomial $\Delta(t)=a_{2n}t^{2n}+\ldots+a_nt^n+\ldots+a_0$ (cf. Alexander invariants). Since the Alexander polynomial of every knot has even degree and is reciprocal (i.e. $a_i=a_{2n-i}$), it suffices to give the set of last coefficients $a_n,\ldots,a_0$; they are indicated in the table. E.g., next to the knot $8_9$ is written $7-5+3-1$. This means that the Alexander polynomial equals $\Delta(t)=-t^6+3t^5-5t^4+7t^3-5t^2+3t-1$. Non-alternating knots are marked by an asterisk (cf. Alternating knots and links). The table is taken from [1] with minor modifications.
Figure: k055590a
References
[1] | G. Burde, "Knoten" , Jahrbuch Ueberblicke Mathematik , B.I. Wissenschaftsverlag Mannheim (1978) pp. 131–147 |
Comments
A table of knots with up to 10 crossings can be found in [a1].
References
[a1] | D. Rolfsen, "Knots and links" , Publish or Perish (1976) |
Knot table. Encyclopedia of Mathematics. URL: http://encyclopediaofmath.org/index.php?title=Knot_table&oldid=31559