A path removing technique for detecting trigger termination

Abstract

Termination decision in trigger systems is to ensure that any rule execution does not result in an infinite loop. Generally, this is an undecidable task. Several recent works have been proposed to prove termination under certain situations. However, most of these existing methods make use of the trigger conditions only in a limited way. In particular, overall conditions of long trigger sequences are not fully used to decide termination. In this paper, we will introduce the activation formula, which considers the overall conditions of long trigger sequences and hence covers many previous works. With this extension, traditional trigger edge elimination methods are no longer sufficient. We will then present a path elimination method called the node splitting method. Using this new approach, more termination situations than existing works can be detected.