Proof Scores in the OTS/CafeOBJ Method

Abstract

Abstract.A way to write proof scores showing that distributed systems have invariant properties in algebraic specification languages is described, which has been devised through several case studies. The way makes it possible to divide a formula stating an invariant property under discussion into reasonably small ones, each of which is proved by writing proof scores individually. This relieves the load to reduce logical formulas and can decrease the number of subcases into which the case is split in case analysis.

Proving Safety Properties of Rewrite Theories

“…Proof scores in the OTS/CafeOBJ method are used to prove invariant properties of concurrent systems specified by observational transition systems [17]. This approach has been applied for verifying safety properties of large specifications, including communication protocols.…”

Towards Reliable E-Government Systems with the OTS/CafeOBJ Method

“…An OTS [5] is used as the formal model in the OTS/CafeOBJ method. We assume that there exists a universal state space called Υ, and that data types used, including the equivalence relation (denoted by =) for each data type, have been defined in advance.…”

“…The use of formal methods to e-Government research and practice has recently been advocated by Jim Davies, et al in [4], and the relevance and opportunities of such usage have been explored as well. The objective of this paper is to make a same advocation as the one by Jim Davies, et al, but we back up this advocation with an experiment on using a specific formal method -the OTS/CafeOBJ method [5] -to model and analyze an e-Government messaging framework [6]- [8]. The framework is proposed for providing citizens with seamless public services * * , and its key idea is to support asynchronous message exchange among registered members (government agencies) through dynamically created and subscribed channels.…”

“…In our experiment, the framework is first modeled as an OTS (Observational Transition System) [5], a kind of state transition system that could be straightforwardly written in terms of equations. The OTS is then specified in CafeOBJ, an algebraic specification language [10], [11].…”

Modeling and Verification of Hybrid Systems Based on Equations

“…In any case, proofs, or proof scores are written in CafeOBJ. A method of writing proof scores of invariants for OTSs is described in Ogata and Futatsugi, 2003c, which can be used for HOTSs. …”