2008/01/02 by Steven Dale Cutkosky, Cutkosky, Steven Dale
Mathematics · #13A18 #13H99 #Algebraic Geometry (math.AG) #Commutative Algebra (math.AC) #FOS: Mathematics #math.AC #math.AG #msc:13A18 #msc:13H99
paper · pdf · doi:10.48550/arxiv.0801.0449
arxiv created 2008/01/02 · arxiv updated 2009/12/01
A new criterion is given for a semigroup to be the semigroup of a valuation dominating an equicharacteristic local domain. The criterion is used to construct examples of well ordered subsemigroups of the positive rational numbers which are of ordinal type omega, but are not the value semigroup of a valuation on an equicharacteristic noetherian local domain. This shows that the necessary conditions on value semigroups given in Appendix 3 to Zariski and Samuel's book ``Commutative Algebra'' are not sufficient.