%0 Journal Article %A Muñoz Masqué, Jaime %A Pozo Coronado, Luis Miguel %A Sánchez Rodríguez, I. %T The prescribed curvature problem in dimension four. %D 2009 %@ 0021-7824 %U https://hdl.handle.net/20.500.14352/50239 %X Necessary and sufficient conditions for a g-valued differential 2-form on a 4-dimensional manifold to be, locally, a curvature; form, are given. The dimension four is exceptional for the problem of prescribed curvature as, in this dimension, Bianchi's identities can be eliminated for a large class of Lie algebras, including semisimple algebras. Hence, the curvature forms are characterized as the solutions to a second-order partial differential system, which is proved to be formally integrable. %~