Z2-twisted fields and bosonization on Riemann surfaces

The equivalence on Riemann surfaces between one Z2-twisted boson and two fermions having different spin structures is proved. The equivalence is shown on the partition function and on the N-point functions. We analyse the consistency between the chiral and the non-chiral definitions of the twisted vertex operator. The equivalence essentially relies upon the eighty year old Schottky-Jung identities. (orig.)