Sign up ×
MathOverflow is a question and answer site for professional mathematicians. It's 100% free, no registration required.

In my S matrix classification attempts I encounter a lot of Dubrovnik polynomials of the form D(z-1/z,z^n) and D(-z+1/z,z^n). [Second variable is for writhe, n is an integer; for the first I don't relate to the skein relation because having a 50:50 chance of sign, I will in 100% choose the false :-)]

Anyway, the one I seek has n=1 and is very easily to describe: All knots evaluate to 1. (Still, e.g. it can detect the mirrors of 6_3_3, the smallest nonalternating link.) Some more values: unlink 2, Hopf z^2+1/z^2, 421 z^4+1/z^4, Whitehead 2

I wouldn't wonder if this specialization of the Dubrovnik polynomial (it's the "other" solution for dimension 2 S matrices besides the Jones) already has a special name. Does it?

share|cite|improve this question
This is probably one of the families SO(2n+1), SO(2n), SP(2n), or OSP(1|2n). Figuring out which requires chasing through a bunch of conventions, but if you look at the background to our paper (with Scott and Emily) you should be able to sort it out. In particular look at page 7 for our conventions for Dubrovnik and the bottom of page 9 for the specializations giving those families. –  Noah Snyder Apr 20 '11 at 16:37
Close enough. (Identified, but not "specially named".) The paper even answers some questions I didn't ask yet :-) –  Hauke Reddmann Apr 21 '11 at 13:50
Right, basically they only get special names if they were discovered and named prior to Reshetikhin-Turaev's work. Anyway which of those families did it turn out to be? I commented instead of answering just because I didn't know which one was the right answer, but it'd be good to actually have an answer posted. –  Noah Snyder May 5 '11 at 18:15

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.