Negation by default and unstratifiable logic programs

摘要: Abstract The default approach to the theory of logic programs (and deductive databases) is based on interpretation negation by rules. Default a well-suited formalism express Closed World Assumption and define declarative semantics stratifiable programs. case disjunctive consequences in rules treated. General may not have meaning with respect semantics. contribution paper exhibit an interesting class having semantics, called effectively This time, are considered. Effective stratification weaker constraint than stratification, local weak stratification. Besides enlarging programs, contributes provide constructive definition well-founded models matches total model general, extends