Irregularity of a Surface (Paperback)

High Quality Content by WIKIPEDIA articles In mathematics, the irregularity of a complex surface X is the Hodge number h0,1= dim H1(OX), usually denoted by q (Wolf P. Barth, Klaus Hulek Chris A.M. Peters et al.2004). The irregularity of an algebraic surface is sometimes defined to be this Hodge number, and sometimes defined to be the dimension of the Picard variety (Bombieri Mumford 1977, p.26), which is the same in characteristic 0 but can be smaller in positive characteristic.