Dorin Popescu: Extensions of valuation rings containing $\bf Q$ as limits of smooth algebras, 253-262

Abstract:

We give a necessary and sufficient condition for an extension of valuation rings containing $\bf Q$ to be a filtered direct limit of smooth algebras.

Key Words: Valuation rings, immediate extensions, pseudo convergent sequences, pseudo limits, Andreé-Quillen homology, smooth morphisms.

2010 Mathematics Subject Classification: Primary 13F30; Secondary 13D03, 13A18, 13B40.

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