|
Mathematics
An analogue of Turaev comultiplication for knots in non-orientable thickening of a non-orientable surface
V. V. Tarkaevab a Chelyabinsk State University, Chelyabinsk, Russia
b Krasovskii Institute of Mathematics and Mechanics of Ural Branch of the Russian Academy of Sciences, Yekaterinburg, Russia
Abstract:
This paper concerns pseudo-classical knots in the non-orientable manifold $\hat{\Sigma} =\Sigma \times [0,1]$,
where $\Sigma$ is a non-orientable surface
and a knot $K \subset \hat{\Sigma}$ is called pseudo-classical if $K$ is orientation-preserving path in $\hat{\Sigma}$.
For this kind of knot we introduce an invariant $\Delta$
that is an analogue of Turaev comultiplication for knots in a thickened orientable surface.
As its classical prototype, $\Delta$ takes value in a polynomial algebra generated by homotopy classes of non-contractible loops on $\Sigma$,
however, as a ground ring we use some subring of $\mathbb{C}$ instead of $\mathbb{Z}$.
Then we define a few homotopy, homology and polynomial invariants,
which are consequences of $\Delta$,
including an analogue of the affine index polynomial.
Keywords:
knots in non-orientable manifold,
knots in thickened surface,
invariants of knots,
Turaev comultiplication,
affine index polynomial.
Received: 30.07.2024 Revised: 08.12.2024
Citation:
V. V. Tarkaev, “An analogue of Turaev comultiplication for knots in non-orientable thickening of a non-orientable surface”, Chelyab. Fiz.-Mat. Zh., 10:1 (2025), 112–125
Linking options:
https://www.mathnet.ru/eng/chfmj426 https://www.mathnet.ru/eng/chfmj/v10/i1/p112
|
|