Recall that a morphism of rings RtoS is called (essentially) smooth if it is formally smooth and (essentially) finitely presented.
(Note: RtoS is essentially finitely presented provided that S is the localization of some finitely
presented R-algebra T at some multiplicative system AsubsetT, that is, S=A−1T.)
In class, our professor said that working with smooth or essentially smooth morphisms yields an effectively equivalent theory. This motivates my question: Is there a general technique to lift results from the smooth case to the essentially smooth case?
Edit: According to Mel, every essentially smooth morphism is a localization of a smooth morphism. However, this direction is much more involved than the other direction, which is immediate from the definitions. Anyway, this would be the answer to the question.
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