Plane curves of genus p and degree 2p as projections of space curves of the same degree

We characterize plane curves Γ of genus p and degree 2p with respect to the possibility of obtaining them as projections of space curves C′ of the same degree. When Γ is hyperelliptic, we link this characterization with the configuration of the singularities of Γ and with the position of C′ on certain scrolls. Supported by the M.U.R.S.T. of the Italian Government