On the role of logic in information retrieval

摘要

The logical approach to information retrieval has recently been the object of active research. It is our contention that researchers have put a lot of effort in trying to address some difficult problems of IR within this framework, but little effort in checking that the resulting models satisfy those well-formedness criteria that, in the field of mathematical logic, are considered essential and conducive to effective modelling of a real-world phenomenon. The main motivation of this paper is not to propose a new logical model of IR, but to discuss some central issues in the application of logic to IR. The first issue we touch upon is the logical relationship we might want to enforce between formulae d, representing a document, and n, representing an information need; we analyse the different implications of models based on truth, validity or logical consequentiality. The relationship between this issue and the issue of partiality vs. totality of information is subsequently analysed, in the context of a broader discussion of the role of denotational semantics in IR modelling. Finally, the relationship between the paradoxes of material implication and the (in)adequacy of classical logic for IR modelling purposes is discussed.