  Open logic programs and open entailment have been recently proposed as an
abstract framework for the verification of incomplete specifications based upon
normal logic programs and the stable model semantics. There are obvious
analogies between open predicates and abducible predicates. However, despite
superficial similarities, there are features of open programs that have no
immediate counterpart in the framework of abduction and viceversa. Similarly,
open programs cannot be immediately simulated with answer set programming
(ASP). In this paper we start a thorough investigation of the relationships
between open inference, abduction and ASP. We shall prove that open programs
generalize the other two frameworks. The generalized framework suggests
interesting extensions of abduction under the generalized stable model
semantics. In some cases, we will be able to reduce open inference to abduction
and ASP, thereby estimating its computational complexity. At the same time, the
aforementioned reduction opens the way to new applications of abduction and
ASP.
