BibTeX
@MISC{Gomes_iospress,
author = {Ana Sofia Gomes and Jose ́ Júlio Alferes},
title = {IOS Press External Transaction Logic: reasoning and},
year = {}
}
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Abstract
Abstract. In this work we present External Transaction Logic, a logic that extends Transaction logic with the ability to model and execute transactions requiring interactions with external entities, as e.g. external web-source, web-services or agents. Transactions are defined in a logic programming style by the composition of internal and external primitives. These primitives are incorporated in a quite general manner, as a parameter of the External Transaction Logic theory, allowing the specification of transactions integrating knowledge and actions from multiple sources and semantics. Since one has different control over internal and external domains, different transaction properties are ensured depending on where actions are executed. Namely, internal actions executed in a knowledge base that we fully control, follow the standard model of transactions, where the failure of the transaction leaves the knowledge unaffected. On the other hand, transactional properties over actions executed externally need to be relaxed, as it is impossible to roll back actions executed in a domain that is external. To deal with this, external actions can be defined along with compensating operations. If a transaction fails after executing some external action, then these compensations are executed in a backward order to achieve a relaxed model of atomicity. We provide a model theory for External Transaction Logic, that can be used to reason about the conditions of execution of transactions that require the issuing of both internal and external actions on abstract knowledge bases with potentially different state semantics. We also present here a corresponding proof theory (sound and complete w.r.t. the model theory) that provides means to execute such transactions in a top-down manner.
Keyphrases
io press external transaction logic external action model theory backward order present external transaction logic external entity relaxed model external domain general manner transaction logic multiple source standard model different transaction property knowledge base different state semantics internal action top-down manner external primitive transactional property external transaction logic external transaction logic theory abstract knowledge base external web-source logic programming style execute transaction corresponding proof theory different control
