Abstract
We give a canonical construction of a balanced big Cohen-Macaulay algebra for a domain of finite type over $\mathbb C$ by taking ultraproducts of absolute integral closures in positive characteristic. This yields a new tight closure characterization of rational singularities in characteristic zero.
Citation
Hans Schoutens. "Canonical big Cohen-Macaulay algebras and rational singularities." Illinois J. Math. 48 (1) 131 - 150, Spring 2004. https://doi.org/10.1215/ijm/1258136178
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