Theta liftings on weak Maass forms
  We construct theta liftings from half-integral weight weak Maass forms to even integral weight weak Maass forms by using regularized theta integral. Moreover it gives an extension of Niwa's theta liftings on harmonic weak Maass forms. And we obtain the similar results to those by Niwa. 
YoungJu Choie, Subong Lim
math.NT