8 18

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8 17.gif

8_17

8 19.gif

8_19

8 18.gif Visit 8 18's page at the Knot Server (KnotPlot driven, includes 3D interactive images!)

Visit 8 18's page at Knotilus!

Visit 8 18's page at the original Knot Atlas!

According to Mathematical Models by H. Martyn Cundy and A.P. Rollett, second edition, 1961 (Oxford University Press), p. 57, a flat ribbon or strip can be tightly folded into a heptagonal 8_18 knot (just as it can be tightly folded into a pentagonal trefoil knot).

This is the Carrick loop of practical knot tying. The Carrick bend of practical knot tying can be found at [math]\displaystyle{ 8^2_{7} }[/math].




Logo of the International Guild of Knot Tyers [1]
A charity logo in Porto [2]
A laser cut by Tom Longtin [3]
Knot in (pseudo-)Celtic decorative form
Less symmetrical
Within outer circle
Impossible figure
Mongolian ornament
Jump rope knot
Belt design
Bondage knot
Spheric depiction
A "Hungarian Knot", decorating French Military uniforms.
Carpet swatter.
Geodesic of the prolate ellipsoid.
Obtained with an epitrochoid.


Knot presentations

Planar diagram presentation X6271 X8394 X16,11,1,12 X2,14,3,13 X4,15,5,16 X10,6,11,5 X12,7,13,8 X14,10,15,9
Gauss code 1, -4, 2, -5, 6, -1, 7, -2, 8, -6, 3, -7, 4, -8, 5, -3
Dowker-Thistlethwaite code 6 8 10 12 14 16 2 4
Conway Notation [8*]

Three dimensional invariants

Symmetry type Fully amphicheiral
Unknotting number 2
3-genus 3
Bridge index 3
Super bridge index 4
Nakanishi index 2
Maximal Thurston-Bennequin number [-5][-5]
Hyperbolic Volume 12.3509
A-Polynomial See Data:8 18/A-polynomial

[edit Notes for 8 18's three dimensional invariants]

Four dimensional invariants

Smooth 4 genus [math]\displaystyle{ 1 }[/math]
Topological 4 genus [math]\displaystyle{ 1 }[/math]
Concordance genus [math]\displaystyle{ [1,3] }[/math]
Rasmussen s-Invariant 0

[edit Notes for 8 18's four dimensional invariants]

Polynomial invariants

Alexander polynomial [math]\displaystyle{ -t^3+5 t^2-10 t+13-10 t^{-1} +5 t^{-2} - t^{-3} }[/math]
Conway polynomial [math]\displaystyle{ -z^6-z^4+z^2+1 }[/math]
2nd Alexander ideal (db, data sources) [math]\displaystyle{ \left\{t^2-t+1\right\} }[/math]
Determinant and Signature { 45, 0 }
Jones polynomial [math]\displaystyle{ q^4-4 q^3+6 q^2-7 q+9-7 q^{-1} +6 q^{-2} -4 q^{-3} + q^{-4} }[/math]
HOMFLY-PT polynomial (db, data sources) [math]\displaystyle{ -z^6+a^2 z^4+z^4 a^{-2} -3 z^4+a^2 z^2+z^2 a^{-2} -z^2-a^2- a^{-2} +3 }[/math]
Kauffman polynomial (db, data sources) [math]\displaystyle{ 3 a z^7+3 z^7 a^{-1} +6 a^2 z^6+6 z^6 a^{-2} +12 z^6+4 a^3 z^5+3 a z^5+3 z^5 a^{-1} +4 z^5 a^{-3} +a^4 z^4-9 a^2 z^4-9 z^4 a^{-2} +z^4 a^{-4} -20 z^4-4 a^3 z^3-9 a z^3-9 z^3 a^{-1} -4 z^3 a^{-3} +3 a^2 z^2+3 z^2 a^{-2} +6 z^2+a z+z a^{-1} +a^2+ a^{-2} +3 }[/math]
The A2 invariant [math]\displaystyle{ q^{12}-2 q^{10}-q^6-q^4+4 q^2+1+4 q^{-2} - q^{-4} - q^{-6} -2 q^{-10} + q^{-12} }[/math]
The G2 invariant [math]\displaystyle{ q^{66}-3 q^{64}+6 q^{62}-10 q^{60}+8 q^{58}-4 q^{56}-5 q^{54}+23 q^{52}-36 q^{50}+48 q^{48}-38 q^{46}+7 q^{44}+28 q^{42}-67 q^{40}+84 q^{38}-71 q^{36}+29 q^{34}+17 q^{32}-58 q^{30}+77 q^{28}-56 q^{26}+8 q^{24}+34 q^{22}-59 q^{20}+45 q^{18}-6 q^{16}-45 q^{14}+81 q^{12}-81 q^{10}+64 q^8-11 q^6-48 q^4+97 q^2-111+97 q^{-2} -48 q^{-4} -11 q^{-6} +64 q^{-8} -81 q^{-10} +81 q^{-12} -45 q^{-14} -6 q^{-16} +45 q^{-18} -59 q^{-20} +34 q^{-22} +8 q^{-24} -56 q^{-26} +77 q^{-28} -58 q^{-30} +17 q^{-32} +29 q^{-34} -71 q^{-36} +84 q^{-38} -67 q^{-40} +28 q^{-42} +7 q^{-44} -38 q^{-46} +48 q^{-48} -36 q^{-50} +23 q^{-52} -5 q^{-54} -4 q^{-56} +8 q^{-58} -10 q^{-60} +6 q^{-62} -3 q^{-64} + q^{-66} }[/math]
Further Quantum Invariants
Further quantum knot invariants for 8_18.

A1 Invariants.

Weight Invariant
1 [math]\displaystyle{ q^9-3 q^7+2 q^5-q^3+2 q+2 q^{-1} - q^{-3} +2 q^{-5} -3 q^{-7} + q^{-9} }[/math]
2 [math]\displaystyle{ q^{26}-3 q^{24}-q^{22}+11 q^{20}-6 q^{18}-12 q^{16}+16 q^{14}-q^{12}-17 q^{10}+11 q^8+6 q^6-10 q^4+2 q^2+9+2 q^{-2} -10 q^{-4} +6 q^{-6} +11 q^{-8} -17 q^{-10} - q^{-12} +16 q^{-14} -12 q^{-16} -6 q^{-18} +11 q^{-20} - q^{-22} -3 q^{-24} + q^{-26} }[/math]
3 [math]\displaystyle{ q^{51}-3 q^{49}-q^{47}+8 q^{45}+6 q^{43}-14 q^{41}-26 q^{39}+20 q^{37}+48 q^{35}-7 q^{33}-70 q^{31}-17 q^{29}+86 q^{27}+44 q^{25}-82 q^{23}-71 q^{21}+65 q^{19}+81 q^{17}-42 q^{15}-87 q^{13}+21 q^{11}+73 q^9+6 q^7-58 q^5-21 q^3+42 q+42 q^{-1} -21 q^{-3} -58 q^{-5} +6 q^{-7} +73 q^{-9} +21 q^{-11} -87 q^{-13} -42 q^{-15} +81 q^{-17} +65 q^{-19} -71 q^{-21} -82 q^{-23} +44 q^{-25} +86 q^{-27} -17 q^{-29} -70 q^{-31} -7 q^{-33} +48 q^{-35} +20 q^{-37} -26 q^{-39} -14 q^{-41} +6 q^{-43} +8 q^{-45} - q^{-47} -3 q^{-49} + q^{-51} }[/math]
4 [math]\displaystyle{ q^{84}-3 q^{82}-q^{80}+8 q^{78}+3 q^{76}-2 q^{74}-28 q^{72}-16 q^{70}+41 q^{68}+56 q^{66}+40 q^{64}-103 q^{62}-153 q^{60}-2 q^{58}+172 q^{56}+269 q^{54}-41 q^{52}-349 q^{50}-286 q^{48}+88 q^{46}+541 q^{44}+295 q^{42}-291 q^{40}-582 q^{38}-260 q^{36}+507 q^{34}+589 q^{32}+29 q^{30}-565 q^{28}-529 q^{26}+216 q^{24}+566 q^{22}+282 q^{20}-309 q^{18}-511 q^{16}-45 q^{14}+349 q^{12}+338 q^{10}-61 q^8-348 q^6-197 q^4+133 q^2+323+133 q^{-2} -197 q^{-4} -348 q^{-6} -61 q^{-8} +338 q^{-10} +349 q^{-12} -45 q^{-14} -511 q^{-16} -309 q^{-18} +282 q^{-20} +566 q^{-22} +216 q^{-24} -529 q^{-26} -565 q^{-28} +29 q^{-30} +589 q^{-32} +507 q^{-34} -260 q^{-36} -582 q^{-38} -291 q^{-40} +295 q^{-42} +541 q^{-44} +88 q^{-46} -286 q^{-48} -349 q^{-50} -41 q^{-52} +269 q^{-54} +172 q^{-56} -2 q^{-58} -153 q^{-60} -103 q^{-62} +40 q^{-64} +56 q^{-66} +41 q^{-68} -16 q^{-70} -28 q^{-72} -2 q^{-74} +3 q^{-76} +8 q^{-78} - q^{-80} -3 q^{-82} + q^{-84} }[/math]
5 [math]\displaystyle{ q^{125}-3 q^{123}-q^{121}+8 q^{119}+3 q^{117}-5 q^{115}-16 q^{113}-18 q^{111}+5 q^{109}+55 q^{107}+75 q^{105}+5 q^{103}-117 q^{101}-199 q^{99}-116 q^{97}+135 q^{95}+429 q^{93}+425 q^{91}-31 q^{89}-637 q^{87}-905 q^{85}-422 q^{83}+649 q^{81}+1500 q^{79}+1200 q^{77}-277 q^{75}-1879 q^{73}-2201 q^{71}-621 q^{69}+1832 q^{67}+3129 q^{65}+1860 q^{63}-1222 q^{61}-3614 q^{59}-3154 q^{57}+104 q^{55}+3538 q^{53}+4145 q^{51}+1191 q^{49}-2871 q^{47}-4563 q^{45}-2378 q^{43}+1862 q^{41}+4404 q^{39}+3127 q^{37}-751 q^{35}-3793 q^{33}-3415 q^{31}-164 q^{29}+2928 q^{27}+3251 q^{25}+827 q^{23}-2050 q^{21}-2874 q^{19}-1163 q^{17}+1281 q^{15}+2369 q^{13}+1365 q^{11}-676 q^9-1958 q^7-1474 q^5+218 q^3+1650 q+1650 q^{-1} +218 q^{-3} -1474 q^{-5} -1958 q^{-7} -676 q^{-9} +1365 q^{-11} +2369 q^{-13} +1281 q^{-15} -1163 q^{-17} -2874 q^{-19} -2050 q^{-21} +827 q^{-23} +3251 q^{-25} +2928 q^{-27} -164 q^{-29} -3415 q^{-31} -3793 q^{-33} -751 q^{-35} +3127 q^{-37} +4404 q^{-39} +1862 q^{-41} -2378 q^{-43} -4563 q^{-45} -2871 q^{-47} +1191 q^{-49} +4145 q^{-51} +3538 q^{-53} +104 q^{-55} -3154 q^{-57} -3614 q^{-59} -1222 q^{-61} +1860 q^{-63} +3129 q^{-65} +1832 q^{-67} -621 q^{-69} -2201 q^{-71} -1879 q^{-73} -277 q^{-75} +1200 q^{-77} +1500 q^{-79} +649 q^{-81} -422 q^{-83} -905 q^{-85} -637 q^{-87} -31 q^{-89} +425 q^{-91} +429 q^{-93} +135 q^{-95} -116 q^{-97} -199 q^{-99} -117 q^{-101} +5 q^{-103} +75 q^{-105} +55 q^{-107} +5 q^{-109} -18 q^{-111} -16 q^{-113} -5 q^{-115} +3 q^{-117} +8 q^{-119} - q^{-121} -3 q^{-123} + q^{-125} }[/math]
6 [math]\displaystyle{ q^{174}-3 q^{172}-q^{170}+8 q^{168}+3 q^{166}-5 q^{164}-19 q^{162}-6 q^{160}+3 q^{158}+19 q^{156}+74 q^{154}+46 q^{152}-37 q^{150}-165 q^{148}-191 q^{146}-117 q^{144}+105 q^{142}+493 q^{140}+615 q^{138}+334 q^{136}-418 q^{134}-1106 q^{132}-1471 q^{130}-907 q^{128}+794 q^{126}+2478 q^{124}+3133 q^{122}+1676 q^{120}-1190 q^{118}-4531 q^{116}-5858 q^{114}-3284 q^{112}+2081 q^{110}+7610 q^{108}+9275 q^{106}+5639 q^{104}-3099 q^{102}-11670 q^{100}-14037 q^{98}-7817 q^{96}+4735 q^{94}+16040 q^{92}+19384 q^{90}+9942 q^{88}-7128 q^{86}-21493 q^{84}-23749 q^{82}-10860 q^{80}+9930 q^{78}+26865 q^{76}+27036 q^{74}+10046 q^{72}-14232 q^{70}-30534 q^{68}-27888 q^{66}-7581 q^{64}+18756 q^{62}+32595 q^{60}+25896 q^{58}+2664 q^{56}-21877 q^{54}-31950 q^{52}-21520 q^{50}+2933 q^{48}+23687 q^{46}+28502 q^{44}+14738 q^{42}-7366 q^{40}-23259 q^{38}-23130 q^{36}-7741 q^{34}+10599 q^{32}+20653 q^{30}+16332 q^{28}+2223 q^{26}-11946 q^{24}-16899 q^{22}-10125 q^{20}+2028 q^{18}+11760 q^{16}+12663 q^{14}+5442 q^{12}-4872 q^{10}-11043 q^8-9364 q^6-1663 q^4+7039 q^2+10561+7039 q^{-2} -1663 q^{-4} -9364 q^{-6} -11043 q^{-8} -4872 q^{-10} +5442 q^{-12} +12663 q^{-14} +11760 q^{-16} +2028 q^{-18} -10125 q^{-20} -16899 q^{-22} -11946 q^{-24} +2223 q^{-26} +16332 q^{-28} +20653 q^{-30} +10599 q^{-32} -7741 q^{-34} -23130 q^{-36} -23259 q^{-38} -7366 q^{-40} +14738 q^{-42} +28502 q^{-44} +23687 q^{-46} +2933 q^{-48} -21520 q^{-50} -31950 q^{-52} -21877 q^{-54} +2664 q^{-56} +25896 q^{-58} +32595 q^{-60} +18756 q^{-62} -7581 q^{-64} -27888 q^{-66} -30534 q^{-68} -14232 q^{-70} +10046 q^{-72} +27036 q^{-74} +26865 q^{-76} +9930 q^{-78} -10860 q^{-80} -23749 q^{-82} -21493 q^{-84} -7128 q^{-86} +9942 q^{-88} +19384 q^{-90} +16040 q^{-92} +4735 q^{-94} -7817 q^{-96} -14037 q^{-98} -11670 q^{-100} -3099 q^{-102} +5639 q^{-104} +9275 q^{-106} +7610 q^{-108} +2081 q^{-110} -3284 q^{-112} -5858 q^{-114} -4531 q^{-116} -1190 q^{-118} +1676 q^{-120} +3133 q^{-122} +2478 q^{-124} +794 q^{-126} -907 q^{-128} -1471 q^{-130} -1106 q^{-132} -418 q^{-134} +334 q^{-136} +615 q^{-138} +493 q^{-140} +105 q^{-142} -117 q^{-144} -191 q^{-146} -165 q^{-148} -37 q^{-150} +46 q^{-152} +74 q^{-154} +19 q^{-156} +3 q^{-158} -6 q^{-160} -19 q^{-162} -5 q^{-164} +3 q^{-166} +8 q^{-168} - q^{-170} -3 q^{-172} + q^{-174} }[/math]

A2 Invariants.

Weight Invariant
1,0 [math]\displaystyle{ q^{12}-2 q^{10}-q^6-q^4+4 q^2+1+4 q^{-2} - q^{-4} - q^{-6} -2 q^{-10} + q^{-12} }[/math]
1,1 [math]\displaystyle{ q^{36}-6 q^{34}+18 q^{32}-38 q^{30}+71 q^{28}-124 q^{26}+188 q^{24}-246 q^{22}+300 q^{20}-322 q^{18}+298 q^{16}-236 q^{14}+111 q^{12}+36 q^{10}-204 q^8+360 q^6-482 q^4+578 q^2-598+578 q^{-2} -482 q^{-4} +360 q^{-6} -204 q^{-8} +36 q^{-10} +111 q^{-12} -236 q^{-14} +298 q^{-16} -322 q^{-18} +300 q^{-20} -246 q^{-22} +188 q^{-24} -124 q^{-26} +71 q^{-28} -38 q^{-30} +18 q^{-32} -6 q^{-34} + q^{-36} }[/math]
2,0 [math]\displaystyle{ q^{32}-2 q^{30}-2 q^{28}+5 q^{26}+2 q^{24}-3 q^{22}-2 q^{20}+5 q^{18}+2 q^{16}-11 q^{14}-2 q^{12}+3 q^{10}-6 q^8-4 q^6+7 q^4+8 q^2+4+8 q^{-2} +7 q^{-4} -4 q^{-6} -6 q^{-8} +3 q^{-10} -2 q^{-12} -11 q^{-14} +2 q^{-16} +5 q^{-18} -2 q^{-20} -3 q^{-22} +2 q^{-24} +5 q^{-26} -2 q^{-28} -2 q^{-30} + q^{-32} }[/math]

A3 Invariants.

Weight Invariant
0,1,0 [math]\displaystyle{ q^{28}-3 q^{26}+7 q^{22}-8 q^{20}+2 q^{18}+11 q^{16}-14 q^{14}-q^{12}+7 q^{10}-12 q^8-2 q^6+9 q^4+4 q^2+4+4 q^{-2} +9 q^{-4} -2 q^{-6} -12 q^{-8} +7 q^{-10} - q^{-12} -14 q^{-14} +11 q^{-16} +2 q^{-18} -8 q^{-20} +7 q^{-22} -3 q^{-26} + q^{-28} }[/math]
1,0,0 [math]\displaystyle{ q^{15}-2 q^{13}+q^{11}-3 q^9-q^5+3 q^3+3 q+3 q^{-1} +3 q^{-3} - q^{-5} -3 q^{-9} + q^{-11} -2 q^{-13} + q^{-15} }[/math]
1,0,1 [math]\displaystyle{ q^{46}-6 q^{44}+15 q^{42}-17 q^{40}-3 q^{38}+48 q^{36}-95 q^{34}+100 q^{32}-28 q^{30}-107 q^{28}+237 q^{26}-277 q^{24}+195 q^{22}+11 q^{20}-243 q^{18}+384 q^{16}-393 q^{14}+209 q^{12}+14 q^{10}-210 q^8+257 q^6-153 q^4+47 q^2+43+47 q^{-2} -153 q^{-4} +257 q^{-6} -210 q^{-8} +14 q^{-10} +209 q^{-12} -393 q^{-14} +384 q^{-16} -243 q^{-18} +11 q^{-20} +195 q^{-22} -277 q^{-24} +237 q^{-26} -107 q^{-28} -28 q^{-30} +100 q^{-32} -95 q^{-34} +48 q^{-36} -3 q^{-38} -17 q^{-40} +15 q^{-42} -6 q^{-44} + q^{-46} }[/math]

A4 Invariants.

Weight Invariant
0,1,0,0 [math]\displaystyle{ q^{34}-2 q^{32}-2 q^{30}+5 q^{28}-2 q^{26}-4 q^{24}+8 q^{22}+7 q^{20}-9 q^{18}-5 q^{16}+4 q^{14}-7 q^{12}-16 q^{10}+12 q^6-4 q^4+7 q^2+24+7 q^{-2} -4 q^{-4} +12 q^{-6} -16 q^{-10} -7 q^{-12} +4 q^{-14} -5 q^{-16} -9 q^{-18} +7 q^{-20} +8 q^{-22} -4 q^{-24} -2 q^{-26} +5 q^{-28} -2 q^{-30} -2 q^{-32} + q^{-34} }[/math]
1,0,0,0 [math]\displaystyle{ q^{18}-2 q^{16}+q^{14}-2 q^{12}-2 q^{10}-q^6+3 q^4+2 q^2+5+2 q^{-2} +3 q^{-4} - q^{-6} -2 q^{-10} -2 q^{-12} + q^{-14} -2 q^{-16} + q^{-18} }[/math]

B2 Invariants.

Weight Invariant
0,1 [math]\displaystyle{ q^{28}-3 q^{26}+6 q^{24}-9 q^{22}+12 q^{20}-14 q^{18}+11 q^{16}-10 q^{14}+5 q^{12}-q^{10}-6 q^8+14 q^6-17 q^4+24 q^2-22+24 q^{-2} -17 q^{-4} +14 q^{-6} -6 q^{-8} - q^{-10} +5 q^{-12} -10 q^{-14} +11 q^{-16} -14 q^{-18} +12 q^{-20} -9 q^{-22} +6 q^{-24} -3 q^{-26} + q^{-28} }[/math]
1,0 [math]\displaystyle{ q^{46}-3 q^{42}-3 q^{40}+3 q^{38}+8 q^{36}+q^{34}-10 q^{32}-6 q^{30}+11 q^{28}+11 q^{26}-5 q^{24}-15 q^{22}-3 q^{20}+11 q^{18}+4 q^{16}-11 q^{14}-9 q^{12}+6 q^{10}+8 q^8-q^6-7 q^4+5 q^2+13+5 q^{-2} -7 q^{-4} - q^{-6} +8 q^{-8} +6 q^{-10} -9 q^{-12} -11 q^{-14} +4 q^{-16} +11 q^{-18} -3 q^{-20} -15 q^{-22} -5 q^{-24} +11 q^{-26} +11 q^{-28} -6 q^{-30} -10 q^{-32} + q^{-34} +8 q^{-36} +3 q^{-38} -3 q^{-40} -3 q^{-42} + q^{-46} }[/math]

D4 Invariants.

Weight Invariant
1,0,0,0 [math]\displaystyle{ q^{38}-3 q^{36}+3 q^{34}-4 q^{32}+8 q^{30}-10 q^{28}+10 q^{26}-9 q^{24}+11 q^{22}-9 q^{20}+3 q^{18}-6 q^{16}+2 q^{12}-11 q^{10}+9 q^8-10 q^6+21 q^4-13 q^2+22-13 q^{-2} +21 q^{-4} -10 q^{-6} +9 q^{-8} -11 q^{-10} +2 q^{-12} -6 q^{-16} +3 q^{-18} -9 q^{-20} +11 q^{-22} -9 q^{-24} +10 q^{-26} -10 q^{-28} +8 q^{-30} -4 q^{-32} +3 q^{-34} -3 q^{-36} + q^{-38} }[/math]

G2 Invariants.

Weight Invariant
1,0 [math]\displaystyle{ q^{66}-3 q^{64}+6 q^{62}-10 q^{60}+8 q^{58}-4 q^{56}-5 q^{54}+23 q^{52}-36 q^{50}+48 q^{48}-38 q^{46}+7 q^{44}+28 q^{42}-67 q^{40}+84 q^{38}-71 q^{36}+29 q^{34}+17 q^{32}-58 q^{30}+77 q^{28}-56 q^{26}+8 q^{24}+34 q^{22}-59 q^{20}+45 q^{18}-6 q^{16}-45 q^{14}+81 q^{12}-81 q^{10}+64 q^8-11 q^6-48 q^4+97 q^2-111+97 q^{-2} -48 q^{-4} -11 q^{-6} +64 q^{-8} -81 q^{-10} +81 q^{-12} -45 q^{-14} -6 q^{-16} +45 q^{-18} -59 q^{-20} +34 q^{-22} +8 q^{-24} -56 q^{-26} +77 q^{-28} -58 q^{-30} +17 q^{-32} +29 q^{-34} -71 q^{-36} +84 q^{-38} -67 q^{-40} +28 q^{-42} +7 q^{-44} -38 q^{-46} +48 q^{-48} -36 q^{-50} +23 q^{-52} -5 q^{-54} -4 q^{-56} +8 q^{-58} -10 q^{-60} +6 q^{-62} -3 q^{-64} + q^{-66} }[/math]

.

Computer Talk
The above data is available with the Mathematica package KnotTheory`, as shown in the (simulated) Mathematica session below. Your input (in red) is realistic; all else should have the same content as in a real mathematica session, but with different formatting. This Mathematica session is also available (albeit only for the knot 5_2) as the notebook PolynomialInvariantsSession.nb.

(The path below may be different on your system, and possibly also the KnotTheory` date)

In[1]:= AppendTo[$Path, "C:/drorbn/projects/KAtlas/"]; << KnotTheory`
Loading KnotTheory` version of August 31, 2006, 11:25:27.5625.

Read more at http://katlas.math.toronto.edu/wiki/KnotTheory.

In[3]:= K = Knot["8 18"];
In[4]:= Alexander[K][t]
KnotTheory::loading: Loading precomputed data in PD4Knots`.
Out[4]= [math]\displaystyle{ -t^3+5 t^2-10 t+13-10 t^{-1} +5 t^{-2} - t^{-3} }[/math]
In[5]:= Conway[K][z]
Out[5]= [math]\displaystyle{ -z^6-z^4+z^2+1 }[/math]
In[6]:= Alexander[K, 2][t]
KnotTheory::credits: The program Alexander[K, r] to compute Alexander ideals was written by Jana Archibald at the University of Toronto in the summer of 2005.
Out[6]= [math]\displaystyle{ \left\{t^2-t+1\right\} }[/math]
In[7]:= {KnotDet[K], KnotSignature[K]}
Out[7]= { 45, 0 }
In[8]:= Jones[K][q]
KnotTheory::loading: Loading precomputed data in Jones4Knots`.
Out[8]= [math]\displaystyle{ q^4-4 q^3+6 q^2-7 q+9-7 q^{-1} +6 q^{-2} -4 q^{-3} + q^{-4} }[/math]
In[9]:= HOMFLYPT[K][a, z]
KnotTheory::credits: The HOMFLYPT program was written by Scott Morrison.
Out[9]= [math]\displaystyle{ -z^6+a^2 z^4+z^4 a^{-2} -3 z^4+a^2 z^2+z^2 a^{-2} -z^2-a^2- a^{-2} +3 }[/math]
In[10]:= Kauffman[K][a, z]
KnotTheory::loading: Loading precomputed data in Kauffman4Knots`.
Out[10]= [math]\displaystyle{ 3 a z^7+3 z^7 a^{-1} +6 a^2 z^6+6 z^6 a^{-2} +12 z^6+4 a^3 z^5+3 a z^5+3 z^5 a^{-1} +4 z^5 a^{-3} +a^4 z^4-9 a^2 z^4-9 z^4 a^{-2} +z^4 a^{-4} -20 z^4-4 a^3 z^3-9 a z^3-9 z^3 a^{-1} -4 z^3 a^{-3} +3 a^2 z^2+3 z^2 a^{-2} +6 z^2+a z+z a^{-1} +a^2+ a^{-2} +3 }[/math]

Vassiliev invariants

V2 and V3: (1, 0)
V2,1 through V6,9:
V2,1 V3,1 V4,1 V4,2 V4,3 V5,1 V5,2 V5,3 V5,4 V6,1 V6,2 V6,3 V6,4 V6,5 V6,6 V6,7 V6,8 V6,9
[math]\displaystyle{ 4 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ 8 }[/math] [math]\displaystyle{ \frac{62}{3} }[/math] [math]\displaystyle{ \frac{34}{3} }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ \frac{32}{3} }[/math] [math]\displaystyle{ 0 }[/math] [math]\displaystyle{ \frac{248}{3} }[/math] [math]\displaystyle{ \frac{136}{3} }[/math] [math]\displaystyle{ \frac{2671}{30} }[/math] [math]\displaystyle{ -\frac{382}{15} }[/math] [math]\displaystyle{ \frac{2942}{45} }[/math] [math]\displaystyle{ \frac{401}{18} }[/math] [math]\displaystyle{ \frac{751}{30} }[/math]

V2,1 through V6,9 were provided by Petr Dunin-Barkowski <barkovs@itep.ru>, Andrey Smirnov <asmirnov@itep.ru>, and Alexei Sleptsov <sleptsov@itep.ru> and uploaded on October 2010 by User:Drorbn. Note that they are normalized differently than V2 and V3.

Khovanov Homology

The coefficients of the monomials [math]\displaystyle{ t^rq^j }[/math] are shown, along with their alternating sums [math]\displaystyle{ \chi }[/math] (fixed [math]\displaystyle{ j }[/math], alternation over [math]\displaystyle{ r }[/math]). The squares with yellow highlighting are those on the "critical diagonals", where [math]\displaystyle{ j-2r=s+1 }[/math] or [math]\displaystyle{ j-2r=s-1 }[/math], where [math]\displaystyle{ s= }[/math]0 is the signature of 8 18. Nonzero entries off the critical diagonals (if any exist) are highlighted in red.   
\ r
  \  
j \
 -4-3-2-101234χ
9        11
7       3 -3
5      31 2
3     43  -1
1    53   2
-1   35    2
-3  34     -1
-5 13      2
-7 3       -3
-91        1
Integral Khovanov Homology

(db, data source)

  
[math]\displaystyle{ \dim{\mathcal G}_{2r+i}\operatorname{KH}^r_{\mathbb Z} }[/math] [math]\displaystyle{ i=-1 }[/math] [math]\displaystyle{ i=1 }[/math]
[math]\displaystyle{ r=-4 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-3 }[/math] [math]\displaystyle{ {\mathbb Z}^{3}\oplus{\mathbb Z}_2 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]
[math]\displaystyle{ r=-2 }[/math] [math]\displaystyle{ {\mathbb Z}^{3}\oplus{\mathbb Z}_2^{3} }[/math] [math]\displaystyle{ {\mathbb Z}^{3} }[/math]
[math]\displaystyle{ r=-1 }[/math] [math]\displaystyle{ {\mathbb Z}^{4}\oplus{\mathbb Z}_2^{3} }[/math] [math]\displaystyle{ {\mathbb Z}^{3} }[/math]
[math]\displaystyle{ r=0 }[/math] [math]\displaystyle{ {\mathbb Z}^{5}\oplus{\mathbb Z}_2^{4} }[/math] [math]\displaystyle{ {\mathbb Z}^{5} }[/math]
[math]\displaystyle{ r=1 }[/math] [math]\displaystyle{ {\mathbb Z}^{3}\oplus{\mathbb Z}_2^{4} }[/math] [math]\displaystyle{ {\mathbb Z}^{4} }[/math]
[math]\displaystyle{ r=2 }[/math] [math]\displaystyle{ {\mathbb Z}^{3}\oplus{\mathbb Z}_2^{3} }[/math] [math]\displaystyle{ {\mathbb Z}^{3} }[/math]
[math]\displaystyle{ r=3 }[/math] [math]\displaystyle{ {\mathbb Z}\oplus{\mathbb Z}_2^{3} }[/math] [math]\displaystyle{ {\mathbb Z}^{3} }[/math]
[math]\displaystyle{ r=4 }[/math] [math]\displaystyle{ {\mathbb Z}_2 }[/math] [math]\displaystyle{ {\mathbb Z} }[/math]

Computer Talk

Much of the above data can be recomputed by Mathematica using the package KnotTheory`. See A Sample KnotTheory` Session.

[math]\displaystyle{ \textrm{Include}(\textrm{ColouredJonesM.mhtml}) }[/math] 

In[1]:=    
 
<< KnotTheory`
 
Loading KnotTheory` (version of August 17, 2005, 14:44:34)...
In[2]:=
Crossings[Knot[8, 18]]
Out[2]=  
8
In[3]:=
PD[Knot[8, 18]]
Out[3]=  
PD[X[6, 2, 7, 1], X[8, 3, 9, 4], X[16, 11, 1, 12], X[2, 14, 3, 13], 
  X[4, 15, 5, 16], X[10, 6, 11, 5], X[12, 7, 13, 8], X[14, 10, 15, 9]]
In[4]:=
GaussCode[Knot[8, 18]]
Out[4]=  
GaussCode[1, -4, 2, -5, 6, -1, 7, -2, 8, -6, 3, -7, 4, -8, 5, -3]
In[5]:=
BR[Knot[8, 18]]
Out[5]=  
BR[3, {-1, 2, -1, 2, -1, 2, -1, 2}]
In[6]:=
alex = Alexander[Knot[8, 18]][t]
Out[6]=  
      -3   5    10             2    3

13 - t   + -- - -- - 10 t + 5 t  - t



           2   t


           t
In[7]:=
Conway[Knot[8, 18]][z]
Out[7]=  
     2    4    6
1 + z  - z  - z
In[8]:=
Select[AllKnots[], (alex === Alexander[#][t])&]
Out[8]=  
{Knot[8, 18], Knot[9, 24], Knot[11, NonAlternating, 85], 
  Knot[11, NonAlternating, 164]}
In[9]:=
{KnotDet[Knot[8, 18]], KnotSignature[Knot[8, 18]]}
Out[9]=  
{45, 0}
In[10]:=
J=Jones[Knot[8, 18]][q]
Out[10]=  
     -4   4    6    7            2      3    4

9 + q   - -- + -- - - - 7 q + 6 q  - 4 q  + q



          3    2   q


          q    q
In[11]:=
Select[AllKnots[], (J === Jones[#][q] || (J /. q-> 1/q) === Jones[#][q])&]
Out[11]=  
{Knot[8, 18]}
In[12]:=
A2Invariant[Knot[8, 18]][q]
Out[12]=  
     -12    2     -6    -4   4       2    4    6      10    12

1 + q    - --- - q   - q   + -- + 4 q  - q  - q  - 2 q   + q



           10                2


           q                 q
In[13]:=
Kauffman[Knot[8, 18]][a, z]
Out[13]=  
                                   2                3      3

    -2    2   z            2   3 z       2  2   4 z    9 z         3



3 + a   + a  + - + a z + 6 z  + ---- + 3 a  z  - ---- - ---- - 9 a z  - 



              a                  2                3     a
                                a                a

                    4      4                        5      5
    3  3       4   z    9 z       2  4    4  4   4 z    3 z
 4 a  z  - 20 z  + -- - ---- - 9 a  z  + a  z  + ---- + ---- + 
                    4     2                        3     a
                   a     a                        a

                               6                7
      5      3  5       6   6 z       2  6   3 z         7
 3 a z  + 4 a  z  + 12 z  + ---- + 6 a  z  + ---- + 3 a z
                              2               a


                              a
In[14]:=
{Vassiliev[2][Knot[8, 18]], Vassiliev[3][Knot[8, 18]]}
Out[14]=  
{0, 0}
In[15]:=
Kh[Knot[8, 18]][q, t]
Out[15]=  
5           1       3       1       3       3      4      3

- + 5 q + ----- + ----- + ----- + ----- + ----- + ---- + --- + 3 q t + 
q          9  4    7  3    5  3    5  2    3  2    3     q t



         q  t    q  t    q  t    q  t    q  t    q  t

    3        3  2      5  2    5  3      7  3    9  4


  4 q  t + 3 q  t  + 3 q  t  + q  t  + 3 q  t  + q  t
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