Bennequin number

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In knot theory, the Bennequin number, or Thurston-Bennequin number, of a front diagram of a Legendrian knot is defined as the writhe of the diagram minus the number of right cusps. The maximum Bennequin number over all possible front diagrams of the Legendrian knot is an Legendrian isotopy invariant of the knot.

[edit] References

• Maximal Thurston-Bennequin_number at The Knot Atlas
• Rudolph, Lee (1997). "The slice genus and the Thurston-Bennequin invariant of a knot". Proceedings of the American Mathematical Society 125: 3049 3050. DOI:10.1090/S0002-9939-97-04258-5. MR1443854.