This is a new heuristic which is called Core First Unit Propagation in MapleLCMdistCBTcoreFirst  sat solver .

 CFUP ( Core First Unit Propagation) heuristic is proposed by Jingchao Chen 在2019年SAT竞赛上。

The basic idea of CFUP ( Core First Unit Propagation) is to prefer core clauses over non-core ones during unit propagation. This can be done by moving core clauses ahead of non-core clauses.