Answer Set Enumeration via Assumption Literals

  • Mario Alviano
  • Carmine DodaroEmail author
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 10037)


Modern, efficient Answer Set Programming solvers implement answer set search via non-chronological backtracking algorithms. The extension of these algorithms to answer set enumeration is nontrivial. In fact, adding blocking constraints to discard already computed answer sets is inadequate because the introduced constraints may not fit in memory or deteriorate the efficiency of the solver. On the other hand, the algorithm implemented by clasp, which can run in polynomial space, requires invasive modifications of the answer set search procedure. The algorithm is revised in this paper so as to make it almost independent from the underlying answer set search procedure, provided that the procedure accepts as input a logic program and a list of assumption literals, and returns either an answer set (and associated branching literals) or an unsatisfiable core. The revised algorithm is implemented in wasp, and compared empirically to the state of the art solver clasp.


Answer Set Programming Enumeration Assumption literals 



This work was partially supported by the National Group for Scientific Computation (GNCS-INDAM), by the Italian Ministry of Economic Development under project “PIUCultura (Paradigmi Innovativi per l’Utilizzo della Cultura)” n. F/020016/01–02/X27, and by the Italian Ministry of University and Research under PON project “Ba2Know (Business Analytics to Know) Service Innovation - LAB”, No. PON03PE_00001_1.


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Copyright information

© Springer International Publishing AG 2016

Authors and Affiliations

  1. 1.Department of Mathematics and Computer ScienceUniversity of CalabriaRende (cs)Italy

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