Jens Lieberum

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We define the Conway skein module C(M) of ordered based links in a 3-manifold M. This module gives rise to C(M)-valued invariants of usual links in M. We determine a basis of the Z[z]-module C(Σ×[0, 1])/Tor(C(Σ×[0, 1])) where Σ is the real projective plane or a surface with boundary. For cylinders over the Möbius strip or the projective plane we derive(More)
We determine explicitly a rational even Drinfeld associator Φ in a completion of the universal enveloping algebra of the Lie superalgebra gl(1|1) ⊕3. More generally, we define a new algebra of trivalent diagrams that has a unique even horizontal group-like Drinfeld associator Φ. The associator Φ is mapped to Φ by a weight system. As a related result of(More)
We calculate the dimensions of the space of Vassiliev invariants coming from the Homfly polynomial of links, and of the space of Vassiliev invariants coming from the Kauffman polynomial of links. We show that the intersection of these spaces is spanned by the Vassiliev invariants coming from the Jones polynomial and from a polynomial called Υ. We also show(More)
We consider vector spaces H n,, and F n,, spanned by the degree-n coefficients in power series forms of the Homfly and Kauff-man polynomials of links with components. Generalizing previously known formulas, we determine the dimensions of the spaces for knots the algebra generated by n H n,1 + F n,1 is a polynomial algebra with dim(H n,1 + F n,1) − 1 = n +(More)