Data-Complexity of the Two-Variable Fragment with Counting Quantifiers
arXiv:0806.1636 · doi:10.1016/j.ic.2009.02.004
Abstract
The data-complexity of both satisfiability and finite satisfiability for the two-variable fragment with counting is NP-complete; the data-complexity of both query-answering and finite query-answering for the two-variable guarded fragment with counting is co-NP-complete.