In dimension 2 there is a very useful criterion, due to Miles Reid, giving a necessary and sufficient condition for an adjoint linear system on a nonsingular complex projective surface X to be free at a point \documentclass[12pt]{minimal}
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\begin{document}$${p\in X}$$\end{document} , in terms of the coherent cohomology of certain divisors on the blowup of X at p. In this note we extend Miles Reid’s result to higher dimensions.