Three talks on noncommutative geometry@n

Notes of three talks given at the workshop 'Hilbert schemes, non-commutative algebra and the McKay correspondence' CIRM-Luminy (France) October 2003. If A is an order over a central normal affine variety X having a stability structure such that the variety of all semi-stable A-representations is a smooth variety, then the corresponding moduli space is a partial desingularization of X and we have a complete classification of the remaining singularities.