作者：Cuypers, H; Steinbach, A
作者单位：Eindhoven University of Technology; Justus Liebig University Giessen
摘要：Most classical groups arising from (anti-) hermitian forms or (pseudo-) quadratic forms contain so-called isotropic transvections. The isotropic transvection subgroups of these classical groups, i.e., the subgroups generated by all isotropic transvections with a fixed axis, form a class Sigma of abelian subgroups which is a class of abstract transvection groups in the sense of Timmesfeld [24]. In this paper we give a common characterization of all these classical groups with isotropic transvec...
作者：Masur, HA; Minsky, YN
作者单位：University of Illinois System; University of Illinois Chicago; University of Illinois Chicago Hospital; State University of New York (SUNY) System; Stony Brook University
作者：Le, TTQ
作者单位：State University of New York (SUNY) System; University at Buffalo, SUNY
摘要：The integrality of the Kontsevich integral and perturbative invariants is discussed. It is shown that the denominator of the degree n part of the Kontsevich integral of any knot or link is a divisor of (2!3!... n!)(4)(n + 1)!. We prove this by establishing the existence of a Drinfeld's associator in the space of chord diagrams with special denominators. We also show that the denominator of the degree n part of the universal perturbative invariant of homology 3-spheres is not divisible by any p...
