From ACT-ONE to Miranda, a Translation Experiment

It is now almost universally acknowledged that the data language ACT-ONE associated with the formal description technique LOTOS is inappropriate for the purpose of OSI formal description. In response to this the LOTOS restandardisation activity plans to replace ACT-ONE with a functional language. Thus, compatibility between ACT-ONE and the replacement data language becomes an issue. In response to this, we present an experimental investigation of backward compatibility between ACT-ONE and the new LOTOS data language. Specifically, we investigate translating ACT-ONE data types into the functional language Miranda. Miranda has been chosen as it is a widely used functional programming language and it is close in form to the anticipated new data language. This work serves as a ``verification of concept'' for translating ACT-ONE to the E-LOTOS data language. It identifies the bounds on embedding ACT-ONE in a functional data language. In particular, it indicates what can be translated and what cannot be translated. In addition, the paper reveals pertinent issues which can inform the E-LOTOS work. For example, which constructs are needed in E-LOTOS in order to support the class of data type specifications typically made in the LOTOS setting? We conclude with a number of specific recommendations for the E-LOTOS data language

Using conditional trace slicing for improving Maude programs

[EN] Understanding the behavior of software is important for the existing software to be improved. In this paper, we present a trace slicing technique that is suitable for analyzing complex, textually-large computations in rewriting logic, which is a general framework efficiently implemented in the Maude language that seamlessly unifies a wide variety of logics and models of concurrency. Given a Maude execution trace T and a slicing criterion for the trace (i.e., a piece of information that we want to observe in the final computation state), we traverse T from back to front and the backward dependence of the observed information is incrementally computed at each execution step. At the end of the traversal, a simplified trace slice is obtained by filtering out all the irrelevant data that do not impact on the data of interest. By narrowing the size of the trace, the slicing technique favors better inspection and debugging activities since most tedious and irrelevant inspections that are routinely performed during diagnosis and bug localization can be eliminated automatically. Moreover, cutting down the execution trace can expose opportunities for further improvement, which we illustrate by means of several examples that we execute by using iJulienne, a trace slicer that implements our conditional slicing technique and is endowed with a trace querying mechanism that increases flexibility and reduction power.This work has been partially supported by the EU (FEDER) and the Spanish MEC project ref. TIN2010-21062-C02-02, and by Generalitat Valenciana ref. PROMETEO2011/052. This work was carried out during the tenure of D. Ballis' ERCIM "Alain Bensoussan" Postdoctoral Fellowship. The research leading to these results has received funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement No. 246016. F. Frechina was supported by FPU-ME grant AP2010-5681 and D. Romero by FPI-MEC grant BES-2008-004860.Alpuente Frasnedo, M.; Ballis, D.; Frechina, F.; Romero, DO. (2014). Using conditional trace slicing for improving Maude programs. Science of Computer Programming. 80:385-415. https://doi.org/10.1016/j.scico.2013.09.018S3854158

Discriminator varieties and symbolic computation

AbstractWe look at two aspects of discriminator varieties which could be of considerable interest in symbolic computation:1.discriminator varieties are unitary (i.e., there is always a most general unifier of two unifiable terms), and2.every mathematical problem can be routinely cast in the form†p1 ≈ q1, …, pk ≈ qk implies the equation x ≈ y.Item (l) offers possibilities for implementations in computational logic, and (2) shows that Birkhoff's five rules of inference for equational logic are all one needs to prove theorems in mathematics

Polynomial Path Orders

This paper is concerned with the complexity analysis of constructor term rewrite systems and its ramification in implicit computational complexity. We introduce a path order with multiset status, the polynomial path order POP*, that is applicable in two related, but distinct contexts. On the one hand POP* induces polynomial innermost runtime complexity and hence may serve as a syntactic, and fully automatable, method to analyse the innermost runtime complexity of term rewrite systems. On the other hand POP* provides an order-theoretic characterisation of the polytime computable functions: the polytime computable functions are exactly the functions computable by an orthogonal constructor TRS compatible with POP*.Comment: LMCS version. This article supersedes arXiv:1209.379