Modular quotient varieties and singularities by the cyclic group of order 2p

摘要

We classify alln-dimensional reduced Cohen-Macaulay modular quotient varieties A(F)(n)/C-2p and study their singularities, wherepis a prime number and C-2p denotes the cyclic group of order 2p. In particular, we present an example that demonstrates that the problem proposed by Yasuda has a negative answer if the condition that "Gis a small subgroup" was dropped.