Is there any notion of an integral $\mathbb{Z}$ cohomology class associated to trefoil knots?
If one considers the trefoil knot in 3 dim, is there any associated integral cohomology class for it?
My understanding and own attempts:
- I know that the trefoil knot and anti-trefoil knot have a different chirality. So this looks that there could be at least a $\mathbb{Z}_2$ cohomology class. Can it be associated with some $\mathbb{Z}$ cohomology class.
What I also found a technical Ref: 0105190-An almost-integral universal Vassiliev invariant of knots. Maybe experts know more.