Universal cocycle Invariants for singular knots and links
Abstract
Given a biquandle $(X, S)$, a function $\tau$ with certain compatibility and a pair of {\em non commutative cocyles} $f,h:X \times X\to G$ with values in a non necessarily commutative group $G$, we give an invariant for singular knots / links. Given $(X,S,\tau)$, we also define a universal group $U_{nc}^{fh}(X)$ and universal functions governing all 2-cocycles in $X$, and exhibit examples of computations. When the target group is abelian, a notion of {\em abelian cocycle pair} is given and the "state sum" is defined for singular knots/links. Computations generalizing linking number for singular knots are given. As for virtual knots, a "self-linking number" may be defined for singular knots
- Publication:
-
arXiv e-prints
- Pub Date:
- October 2019
- DOI:
- 10.48550/arXiv.1910.04042
- arXiv:
- arXiv:1910.04042
- Bibcode:
- 2019arXiv191004042F
- Keywords:
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- Mathematics - Geometric Topology;
- 57M25;
- 57M27
- E-Print:
- 27 pages, 9 figures