High Quality Content by WIKIPEDIA articles! In mathematics, more particularly in the field of algebraic geometry, a scheme X has rational singularities, if it is normal, of finite type over a field of characteristic zero, and there exists a proper birational map f colon Y rightarrow X from a regular scheme Y such that the higher direct images of f applied to mathcal{O}_Y are trivial. That is, R^i f_ mathcal{O}_Y = 0 for i 0.If there is one such resolution, then it follows that all resolutions share this property, since any two resolutions of singularities can be dominated by a third.For surfaces, rational singularities were defined by (Artin 1966).