Simple Reasoning with Time-Dependent Propositions
Makram Bouzid · Logic Journal of IGPL · 2002
Simple practical reasoning with propositions whose truth values depend on time is a matter of logical engineering. One needs an expressive language in which simple inferences are productive. Here's one approach, along with some algorithms for implementing it. We also consider reified and non-reified logics, and show that, contrary to a claim of Bacchus et. al., a reified logic is more appropriate than its non-reified equivalent, even for Boolean logic, when time references are interpreted as union-of-convex intervals. 1 Introduction Many simple propositions may be true at one time and false at another. Any database containing data from the real world must consider such a possibility, and there are various ways of timestamping entries in relation tables (i.e., atomic formulae) to reflect temporal dependencies. However, not everything can easily be configured as relations amongst atomic formulae. Sometimes it is best to maintain small databases and use rapid inferences. What sort of rap...