Higher Order Differential Calculus on
arXiv:q-alg/9708013 · doi:10.1023/A:1021614302046
Abstract
Let be an -dimensional bicovariant first order differential calculus on a Hopf algebra . There are three possibilities to construct a differential Z-graded Hopf algebra which contains as its first order part. Let be a transcendental complex number. For these three Z-graded Hopf algebras coincide. For Woronowicz' external algebra we calculate the dimensions of the spaces of left-invariant and bi-invariant -forms. In this case each bi-invariant form is closed. In case of calculi on the universal calculus is strictly larger than the other two calculi. In particular, the bi-invariant 1-form is not closed.
8 pages, LaTeX2e, uses packages bbm, amsmath, mathrsfs. Presented at the 6th Colloquium "QG & IS", Prag, July 97