Quantified Equality Constraints

An equality template (also equality constraint language) is a relational structure with infinite universe whose relations can be defined by boolean combinations of equalities. We prove a complete complexity classification for quantified constraint satisfaction problems (QCSPs) over equality templates: these problems are in L (decidable in logarithmic space), NP-complete, or PSPACE-complete. To establish our classification theorem we combine methods from universal algebra with concepts from model theory.

• Type: Journal
• Year: 2010
• Where: SIAMCOMP
• Authors: Manuel Bodirsky, Hubie Chen
• Keywords: Complete Complexity Classification, Constraint Satisfaction Problems, Equality Templates, SIAMCOMP 2010