Uwe Semmelmann Eigenvalue estimates for manifolds with special holonomy In my talk I will discuss several mostly well-known results on the kernel and the minimal eigenvalue of the Laplacian on compact manifolds with special holonomy. The new point will be the introduction of an operator generalizing the Laplacian on forms and a general method of producing Weitzenboeck formulas. My aim is to demonstrate that these two tools may lead to a better understanding and hopefully also to new results in the differential geometry of manifolds with special holonomy.