  (To appear in Theory and Practice of Logic Programming (TPLP)) We introduce a
systematic, concurrent execution scheme for Constraint Handling Rules (CHR)
based on a previously proposed sequential goal-based CHR semantics. We
establish strong correspondence results to the abstract CHR semantics, thus
guaranteeing that any answer in the concurrent, goal-based CHR semantics is
reproducible in the abstract CHR semantics. Our work provides the foundation to
obtain efficient, parallel CHR execution schemes.
