José Júlio Alferes

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Traditionally, a logic program is built up to reason about atomic first-order formulas. The key idea of parametrized logic program- ming is that, instead of atomic first-order formulas, a parametrized logic program reasons about formulas of a given parameter logic. Of course, the main challenge is to define the semantics of such general programs. In this work we introduce the novel definitions along with some motivating examples. This approach allows us to prove general results that can be instantiated for every particular choice of the parameter logic. Impor- tant general results we can prove include the existence of semantics and the alternating fix-point theorem of well-founded semantics. To reenforce the soundness of our general framework we show that some known approaches in the literature of logic programming, such as paraconsistent answer-sets and the MKNF semantics for hybrid knowledge bases, are obtained as particular choices of the parameter logic.

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Event-Condition-Action languages are the commonly accepted para- digm to express and model the behavior of reactive systems. While numerous Event-Condition-Action languages have been proposed in the literature, differing e.g. on the expressivity of the language and on its operational behavior, existing Event-Condition-Action languages do not generally support the action compo- nent to be formulated as a transaction. In this paper, sustaining that it is important to execute transactions in reactive languages, we propose an Event-Condition- Transaction language, based on an extension of Transaction Logic. This exten- sion, called Transaction Logic with Events (T Rev ), combines reasoning about the execution of transactions with the ability to detect complex events. An impor- tant characteristic of T Rev is that it takes a choice function as a parameter of the theory, leaving open the behavioral decisions of the logic, and thereby allowing it to be suitable for a wide-spectrum of application scenarios like Semantic Web, multi-agent systems, databases, etc. We start by showing how T Rev can be used as an Event-Condition-Action language where actions are considered as transac- tions, and how to differently instantiate this choice function to achieve different operational behaviors. Then, based on a particular operational instantiation of the logic, we present a procedure that is sound and complete w.r.t. the semantics and that is able to execute T Rev programs

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