FAMILIES OF RIEMANN SURFACES OVER THE PUNCTURED DISK

We study holomorphic families of compact Riemann surfaces over the punctured unit disk. For every genus p greater-than-or-equal-to 3 we define a family whose relative canonical bundle has no roots of order n > 2. The monodromy group of that family is generated by a product of powers of commuting Dehn twists. We give necessary and sufficient conditions for such a product to generate the monodromy group of a family over the punctured disk.