T. Bolognesi and S. A. Smolka. Fundamental results for the verification of observational equivalence: a survey. In H. Rudin and C. H. West, editors, Protocol Specification, Testing, and Verification, VII, Zrich, Switserland, pages 165--178. North-Holland, May 1987.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....with ai T, then F H iI ai.Fi H I The LTS associated to E H can be obtained from the LTS of E by adding all the possible H transitions to any transition and all the possible H self loops. Note that weak bisimilarity is usually tested through strong bisimilation on trans formed processes (see [4]) 10 Example 3. Let H h, h2 and consider the process E defined by the follow ing system E=r.F F = h.E We have that E s is process defined by the following system E H = F H h.F H h2.F H h.E H h2.E H F H = h.E H h.F H h2.F H , q; h I ,h 2 hi ,h 2 ( h 1 ,h2 hi hi ....

T. Bolognesi and S. A. Smolka. Fundamental results for the verification of observational equivalence: A survey. In H. Rudin and C. H. West, editors, Prooc. oflnt'l Conference on Protocol Specification, Testing and Verification (PSTV'87), pages 165-179. North-Holland, 1987.

....Indeed, the computation of bisimulation can be used for reducing to a canonical form with respect to the number of states and for comparing canonical forms. Thus, an e#cient algorithm computing bisimulation equivalence reveals itself quite useful for deciding the other equivalence relations [2] [3], 10] 11] Kanellakis and Smolka [10] studied the connection between the relational coarsest partition problem and the bisimulation equivalence. They proposed an algorithm running in O(mn) time. For the case in which the image set sizes are bounded by a constant c, they gave an algorithm ....

T. Bolognesi and S.A. Smolka. Fundamental results for the verification of observational equivalence. In H.Rudin and C.H. West, editors, Protocol Specification, Testing and Verification VII, 1987.

....1 illustrates the different steps in a traditional engineering process: analysis, requirements capture, design, implementation, and evolution. The formal methods are principally concerned with maintaining correctness, the property that an abstract model fulfils a set of well defined requirements [2, 4, 8, 7], between the initial customer oriented requirements model and the final implementation oriented design. The formal boundaries break down at either end of the software development process because, in general, target implementation languages are not formally defined and customer understanding of ....

T. Bolognesi. Fundamental results in the verification of observational equivalence: a survey. In H. Rudin and W. C.H., editors, Protocol Specification, Testing and Verification VII. North-Holland, 1988.

....occurs within a sub term of p with form :q, it is unguarded otherwise. We assume that all the constant bodies are guarded. Moreover, p is said finite if SOS(p) has a finite number of states. In the paper we consider only finite CCS terms. Syntactic characterizations of finite terms can be found in [2, 21]. 2.1 Notations Let be a relation between terms. We use the following notations. Given a term p, we write p 6 , if no p 0 ; exist such that p p 0 ; while we write p (p ) if p 0 exists such that p p 0 (p 0 and exist such that p p 0 ) Given a term p, we denote by ....

T. Bolognesi, S. Smolka. Fundamental results for the verification of observational equivalence: a survey. In Proc. IFIP WG 6.1 7th Conference on Protocol Specification, Testing and Verification. Amsterdam: North-Holland 1987.

....occurs within a sub term of p with form :q, it is unguarded otherwise. We assume that all the constant bodies are guarded. Moreover, p is said finite if SOS(p) has a finite number of states. In the paper we consider only finite CCS terms. Syntactic characterizations of finite terms can be found in [2, 14]. 2.1 Notations Let be given a relation between terms. We use the following notations. Given a term p, we write p 6 , if no p 0 ; exist such that p p 0 ; while we write p (p ) if p 0 exists such that p p 0 (p 0 and exist such that p p 0 ) Given a term p, we denote ....

T. Bolognesi, S. Smolka. Fundamental results for the verification of observational equivalence: a survey. In Proc. IFIP WG 6.1 7th Conference on Protocol Specification, Testing and Verification. Amsterdam: North-Holland 1987.

.... Most of the existing verification environments [1, 5, 10, 11] for CCS like languages are based on an internal finite state representation of the processes; this allows the verification of logical properties and the application of efficient algorithms to decide whether two processes are bisimilar [2, 12, 13]. It is well known that it is undecidable whether a CCS term is finite state, unless it is expressed in suitable subsets of the language [22] The only known criteria which build a finite transition system for a CCS term either impose syntactic restrictions on the language [2, 15] or they are ....

.... are bisimilar [2, 12, 13] It is well known that it is undecidable whether a CCS term is finite state, unless it is expressed in suitable subsets of the language [22] The only known criteria which build a finite transition system for a CCS term either impose syntactic restrictions on the language [2, 15], or they are defined in terms of an attempt of building a finite transition system [22, 8] while the construction fails on the occurrence of some stopping condition. The constructions are not complete, since there are finite state CCS terms for which the constructions fail. This problem can be ....

[Article contains additional citation context not shown here]

T. Bolognesi, S. Smolka. Fundamental results for the verification of observational equivalence: a survey. In Proc. IFIP WG 6.1 7th Conference on Protocol Specification, Testing and Verification. Amsterdam: NorthHolland 1987. 14

.... most of the existing verification environments [1, 7, 13, 14] for CCS like languages are based on an internal finite state representation of the processes, allowing the verification of logical properties and the application of efficient algorithms to decide whether two processes are bisimilar [2, 16, 17]. Consider the program: P 0 : h x def = a:b:xnfcg c:x; y def = b:y; z def = d: x j y)nfbg; zi Note that SOS(P 0 ) is infinite. We unfold the definition of the constant z using the definitions of x and y in P 0 : P 2 : h x def = a:b:xnfcg c:x; y def = b:y; z def = d: a:b:xnfcg ....

T. Bolognesi, S. Smolka. Fundamental results for the verification of observational equivalence: a survey. In Proc. IFIP WG 6.1 7th Conference on Protocol Specification, Testing and Verification. Amsterdam: North-Holland 1987.

....i N, Node (SRGi 1) Node (SRGi) and all obtained SRGi are homomorphic to SRG0. Algorithm The iterative algorithm presented here converges to the computation of the quasi minimal srg since the set of nodes of SRG0 is finite. This algorithm uses the same technique which has been already used in [1] for computing the strong bisimulation on a LTS: the computation of SRGi 1 considers only predecessor nodes of the new equivalence classes which are just be obtained from the computation of SRGi, and not all the Ri equivalence classes. The procedures used by the algorithm are: Predecessor ....

: T. Bolognesi, S.A. Smolka. "Fundamental results for the verification of observational equivalence", a survey; In: H. Rudin, C.West (eds), Protocol Specification Testing and Verification VII, north Holland (1987) pp 165-179.

....1 the computation of bisimulation can be used for reducing to a canonical form with respect to the number of states and for comparing canonical forms. Thus, an efficient algorithm computing bisimulation equivalence reveals itself quite useful for deciding the other equivalence relations [2] [3], 10] 11] Kanellakis and Smolka [10] studied the connection between the relational coarsest partition problem and the bisimulation equivalence. They proposed an algorithm running in O(mn) time. For the case in which the image set sizes are bounded by a constant c, they gave an algorithm ....

....points to X 1 and X 23 and X 23 points to X 2 and X 3 . 4. 2 Example Consider the following labeled transition system (Q; A; T ; q 0 ) ffl Q = f0; 1; 2; 3; 4; 5g ffl A = fa; b; cg ffl T a [0] f1g; T a [1] f2g; T a [2] f1g ffl T b [0] f3g; T b [1] f3; 4g; T b [2] f4g 12 ffl T c [3] = f5g; T c [4] f5g We start with universal partition 0 = fB 0 g where B 0 = f0; 1; 2; 3; 4; 5g and W = fB 0 g. We decompose info b in info a;B , info b;B and info c;B . We represent info ff;B with its graph. 1. refinement with respect to B 0 (a) label a T Gamma1 a [B 0 ] f0; 1; 2g B 1 ....

T. Bolognesi and S.A. Smolka. Fundamental results for the verification of observational equivalence. In H.Rudin and C.H. West, editors, Protocol Specification, Testing and Verification VII, 1987.

....unrolling of the recursion. Rec(2) is the unique solution to guarded equations. Finally Rec(3) allows the elimination of unguarded variables. March 22, 1995 28 4.7.1 Characterization of FS Processes The definition of finite state agents. that previous authors have used, such as [44] and [15], has been processes coded without the parallel operator, and since the restriction operator becomes useless in this environment, it has been eliminated as well. This simple solution does not work for ACSR because infinite state agents can be generated even without the use of the parallel operator ....

T. Bolognesi and S.A. Smolka. Fundamental Results for the Verification of Observational Equivalence. In Protocol Specification, Testing and Verification. North-Holland, 1987.

....are isomorphic after deletion of all V al parameters. This observation allows the transfer of results according to the number of states resulting from specifications including recursion and the classification of operators which originally have been proved for (untimed) CCS specifications in [21, 3] 1 . To be more general, all results about the qualitative behaviour of a MPA specification can be gained from the untimed specification, the introduction of time does not modify the qualitative behaviour. This observation is true as long as we introduce exponential delays with finite rates and ....

....r) B (a 2 Act) or P i B i . ffl weakly guarded in an expression A if every occurrence of X in some subexpression of A is of the form (a; r) B with a 2 Act. If the static combinators composition and hiding do not occur inside recursion (i.e. all variables are sequential) it can be shown (see [3, 21]) that the MTS underlying a finite specification is also finite. Thus we assume that all free variables are sequential and weakly guarded in their subexpressions. Many real life models are finite state and can be expressed in our calculus. Additionally the finiteness of the MTS allows, at least ....

[Article contains additional citation context not shown here]

T. Bolognesi, S.A. Smolka; Fundamental Results for the Verification of Observational Equivalence: A Survey; in: H. Rudin, C. West (eds.), Protocol Specification, Testing and Verification VII, North Holland (1987) 165-179.

....which aid the development of computer systems. Formal methods are fundamentally concerned with correctness: the property that an abstract model fulfils a set of well defined requirements. This notion is addressed in a number of different texts and with respect to a number of different models, see [9, 10, 8, 15, 43, 34] for example. A major problem when using formal methods in software engineering is that much of the recent research places emphasis on analysis rather than synthesis. The means of constructing complex formal models is often overlooked in favour of techniques for analysing models. In this thesis, ....

....the (de)composition is hierarchical. There has also been much work in defining hierarchical relationships between processes, based on the behaviour they offer. For example, there are many inter process relationships which attempt to model subclassing and implementation properties, see for example [9, 33, 8]. Given the structural expressiveness of the process algebra part of LOTOS alone, we must question why the ADT part is required. The ACT ONE is necessary for defining (or modelling) the following: ffl Parameterised behaviours in the shape of parameterised process definitions. ffl Systems with ....

[Article contains additional citation context not shown here]

T. Bolognesi. Fundamental results in the verification of observational equivalence: a survey. In H. Rudin and West C.H., editors, Protocol Specification, Testing and Verification VII. North-Holland, 1988.

....MRP based on these results the MRP can be reduced to a smaller but equivalent representation and equivalence of two MRPs can be established. This approach is well known in the area of qualitative system analysis to define strong or observational equivalence of different specifications (see e.g. [1, 10]) Let R S Theta S be a binary relation on the state space of a MRP. We use the notation (x; y) 2 R that x and y are in relation R, additionally we define R Gamma1 (x) fyj(x; y) 2 Rg : Definition 2 Let X be a MRP with state space S = f1; ng, generator matrix Q, reward vector r ....

T. Bolognesi, S.A. Smolka; Fundamental results for the verification of observational equivalence: a survey; In: H. Rudin, C. West (eds.), Protocol Specification, Testing and Verification VII, North Holland (1987) 165-179.

....illustrates the different steps in a traditional engineering process: analysis, requirements capture, design, implementation, and evolution. The formal methods are principally concerned with maintaining correctness, the property that an abstract model fulfils a set of well defined requirements [1,2,6,5], between the initial customer oriented requirements model and the final implementation oriented design. The formal boundaries break down at either end of the software development process because, in general, target implementation languages are not formally defined and customer understanding of ....

T. Bolognesi. Fundamental results in the verification of observational equivalence: a survey. In H. Rudin and West C.H., editors, Protocol Specification, Testing and Verification VII. North-Holland, 1988.

....equivalence relation or preorder relation on LTS. Bisimulation equivalences and simulations equivalences or preorders play a central role in the verification of communicating systems. Many efficient algorithms for computing various bisimulation equivalences (strong, weak, branching) were proposed [24, 2, 28, 8, 25, 29, 14, 10, 3]. According to the definition of an equivalence relation which is either a set of state classes or a binary relation on the state space, the methods consists of refining a current partition until each class is stable or checking if a pair of states belonging to the current relation are bisimilar. ....

T. Bolognesi and S.A. Smolka. Fundamental results for the verification of observational equivalence. In H.Rudin and C.H. West, editors, Protocol Specification, Testing and Verification VII, 1987.

....are equivalent can be proved equivalent using these tools. We note however, that this must be true of any method for equivalence checking, as most of the relations we deal with are undecidable. Constraints on the syntactic structure of a process which ensure finiteness have been developed in [BS87, MV91a] The partition method also suffers from the state explosion problem, i.e. if the size of the graph gets too big, which happens easily when parallel statements include several components, the algorithm may become too slow to make its use practical. A further drawback of the original ....

T. Bolognesi and S.A. Smolka. Fundamental Results for the Verification of Observational Equivalence: a Survey. In H. Rudin and C.H. West, editors, Protocol Specification, Testing, and Verification, VII, pages 165--179. Elsevier Science Publishers B.V. (North-Holland), 1987.

....[34] with the algorithm btc, which was ranked the best algorithm for large inputs by Ioannidis et al. 26] Transitive closure computation is a basic computational task. It is required, for instance, in the reachability analysis of transition networks representing distributed and parallel systems [8] and in the construction of parsing automata in compiler construction [6] Recently, efficient transitive closure computation has been recognized as a significant subproblem in evaluating recursive database queries, since almost all practical recursive queries are transitive [10] Because of the ....

Bolognesi and Smolka. Fundamental results for the verification of observational equivalence: A survey. In Proceedings of the IFIP Int. Conf. on Protocol Specification, Testing and Verification VII. North-Holland, 1988. 16

.... is an equivalence relation since it is obviously reflexive and symmetric, by the previous arguments we can also conclude that it is transitive. The inductive definition of is strongly related to the inductive definition of strong equivalence for untimed process algebras as given in [2] and it is indeed the case that is a strong bisimulation, if timing informations are neglected (see [5, 6] Thus is a natural extension of strong equivalence preserving, apart from qualitative also quantitative aspects of an agent. The following theorem shows that is a congruence for ....

T. Bolognesi, S.A. Smolka; Fundamental results for the verification of observational equivalence: a survey; in: H. Rudin, C. West (eds.), Protocol Specification, Testing and Verification VII, North Holland (1987) 165-179.

....1 : p 1 a Gamma T r 1 r 1 i r 2 ) g: Proposition 2.1 is an equivalence relation on (or a partition of) Q. Proof. By the fact that if i is an equivalence relation then i 1 is an equivalence relation. 2 The connection with the relational coarsest partition problem was established in [4], 6] and [11] Let ae be a partition of Q. ae is compatible with T if and only if the following property holds: ae) 8a 2 A : 8B; B 0 2 ae : B 0 T Gamma1 a [B] B 0 T Gamma1 a [B] Given an initial partition ae 0 , the set of partition ordered by refinement as a ....

T. Bolognesi and S.A. Smolka. Fundamental results for the verification of observational equivalence. In H.Rudin and C.H. West, editors, Protocol Specification, Testing and Verification VII, 1987.

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T. Bolognesi and S. A. Smolka. Fundamental results for the verification of observational equivalence: a survey. In H. Rudin and C. H. West, editors, Protocol Specification, Testing, and Verification, VII, Zrich, Switserland, pages 165--178. North-Holland, May 1987.

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T. Bolognesi and S.A. Smolka. Fundamental results for the verification of observational equivalence: a survey. In H. Rudin and C.H. West, editors, Protocol Specification, Testing, and Verification, VII, Zurich, Switserland, pages 165-- 178. North-Holland, May 1987.

No context found.

T. Bolognesi and S.A. Smolka. Fundamental results for the verification of observational equivalence: a survey. In H. Rudin and C.H. West, editors, Protocol Specification, Testing, and Verification, VII, Zurich, Switserland, pages 165-- 178. North-Holland, May 1987.

No context found.

T. Bolognesi and S.A. Smolka. "Fundamental Results for the Verification of Observational Equivalence." Protocol Specification, Testing and Verification, VII, H.Rudin and C.H.West (editors), pp.165--179, 1987 (North Holland).

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T. Bolognesi, S. A. Smolka, "Fundamental Results for the Verification of Observational Equivalence: a Survey", proc. of the IFIP 7 th Internaional Symposium on Protocol Specification, Testing, and Verification, North-Holland, 1987

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T. Bolognesi and S.A. Smolka. Fundamental Results for the Verification of Observational Equivalence: a Survey. In H. Rudin and C.H. West, editors, Protocol Specification, Testing, and Verification, VII, pages 165--179. Elsevier Science Publishers B.V. (North-Holland), 1987.

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