Title of article :
Decidability properties for fragments of CHR
Author/Authors :
Maurizio Gabbrielli، نويسنده , , JACOPO MAURO، نويسنده , , MARIA CHIARA MEO and JON SNEYERS، نويسنده ,
Issue Information :
روزنامه با شماره پیاپی سال 2010
Pages :
16
From page :
611
To page :
626
Abstract :
We study the decidability of termination for two CHR dialects which, similarly to the Datalog like languages, are defined by using a signature which does not allow function symbols (of arity > 0). Both languages allow the use of the = built-in in the body of rules, thus are built on a host language that supports unification. However each imposes one further restriction. The first CHR dialect allows only range-restricted rules, that is, it does not allow the use of variables in the body or in the guard of a rule if they do not appear in the head. We show that the existence of an infinite computation is decidable for this dialect. The second dialect instead limits the number of atoms in the head of rules to one. We prove that in this case, the existence of a terminating computation is decidable. These results show that both dialects are strictly less expressive1 than Turing Machines. It is worth noting that the language (without function symbols) without these restrictions is as expressive as Turing Machines.
Keywords :
Expressivity , well-structured transition systems , Constraint programming
Journal title :
theory and practice of logic programming
Serial Year :
2010
Journal title :
theory and practice of logic programming
Record number :
660657
Link To Document :
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