Wed May 9 12:43:46 CEST 2007 Corrected the indices in 1(e) of Hausaufgaben. Thanks to Felix Janda for noticing the misprint. +---------------------------+ Fri May 11 10:44:28 CEST 2007 Corrected the apostrophe of the e-tensor in 1(c) of Hausaufgaben. Thanks to Matthias Leiß for noticing the misprint.