Eichler Cohomology of Generalized Modular Forms of Real Weights
  In this paper, we prove the Eichler cohomology theorem of weakly parabolic generalized modular forms of real weights on subgroups of finite index in the full modular group. We explicitly establish the isomorphism for large weights by constructing the map from the space of cusp forms to the cohomology group. 
Wissam Raji
math.NT