P. Degano and C. Priami. Non-interleaving semantics for mobile processes. Theoretical Computer Science, 216(1-2):237270, 1999.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....CCS R system (see example 1 below) We will write P # P # , meaning there is a succession of transitions, including possibly zero, starting from P and leading to P # . 6 2. 5 Causality and Backtrack Labels in our transition system are not unlike proof terms used to label CCS transitions in [14, 15]. The original motivation for introducing these proof terms was to have enough information to analyze the causal dependencies between actions. Not every action done after an action a is actually depending on a. For example, both a b and a.b can produce the computation trace a b, but only in the ....

Pierpaolo Degano and Corrado Priami. Non interleaving semantics for mobile processes. In Automata, Languages and Programming, volume 944 of LNCS, pages 660--667. Springer Verlag, 1995. 16

.... proofs are called proved transition systems (PTSs) in [10] Now, Degano and Priami have developed a framework to derive both interleaving and truly concurrent semantic models for CCS and Maggiolo Schettini and Tini Applying techniques of asynchronous concurrency 5 calculus, in [10] and [11]. In these papers, a PTS is taken as the most concrete model of the considered process algebra, and more abstract models are obtained by relabeling the PTS by means of observation functions [9] namely functions which relabel the PTS by maintaining only part of the information carried by labels. ....

....[ n 1 [ i=1 (l i ;l i 1 ) Given # and # 0 0 such that (# ; # 0 0 ) 27 (l 1 ; l n ) we say that # is a local cause of # 0 0 . Locality relations have been extensively studied also for asynchronous process algebras, such as CCS and calculus (as examples, see [10, 11]) These relations are de ned over transitions and not over proof terms, since each PTS transition is labeled by exactly one proof term. Our de nition of locality relation is technically more complex w.r.to those in [10, 11] The reason is that CCS and calculus o er a pre xing operator that ....

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Degano, P. and Priami, C.: \Non interleaving semantics of mobile processes", Theoretical Computer Science, 216, 1999, 237-270.

.... semantics, e.g. 16, 8, 15, 32, 58] The two seem to have been carried out almost independently to our knowledge, the only works to make precise connections are [16, 8, 58] Moreover, only the syntactic approach has been developed to address name passing, in the annotated operational models of [6, 18]. There is also work that does not t this categorisation, having both syntactic and model theoretic aspects, with Petri nets and graph rewriting [9, 42] Our goal in the second half of this paper is to develop the model theoretic approach, and to make precise connections to the annotated ....

....name passing [3, 55, 58] This is precisely related to causal bisimulation [6] In CCS causal dependency arises from pre xing in the behaviour of the process x:y:0 the y output causally depends on the x output. In calculus, name binding introduces new dependencies, as thoroughly discussed in [18]. Transitions occurring in di erent parallel components of a process term, naively regarded as independent, may be forced to occur in a xed order. For example, in the process ( y) xy j yz) the transition yz can be observed only after xy before this occurs the new bound channel is not known to ....

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P. Degano and C. Priami. Non-interleaving semantics for mobile processes. Theoretical Computer Science, 216(1-2):237-270, 1999.

....0 Table 1. Transition system for CCS. As anticipated in the introduction, we enrich the labels of the standard interleaving transition system of CCS in the style of [7,15] It is thus possible to derive different semantic models for CCS by extracting new kinds of labels from the enriched ones (see [17,18]) We start with the definition of the enriched labels and of a function ( that takes them to the corresponding action labels. Definition 1. Let # 2 fjj 0 ; jj 1 g . Then proof terms (with metavariable 2 Theta) are defined by the following syntax : # j #hjj 0 # 0 0 ; jj 1 # 1 1 i ....

P. Degano and C. Priami. Non interleaving semantics for mobile processes. Extended abstract. In Proceedings of ICALP'95, LNCS 944, pages 660--671. SpringerVerlag, 1995. To appear in TCS.

.... BC88, DD89, Kie94, WN95] The two seem to have been carried out almost independently to our knowledge, the only works to make precise connections are [DDNM88a, BC88, WN95] Moreover, only the syntactic approach has been developed to address name passing, in the annotated operational models of [BS98, DP99]. There is also work that does not t this categorisation, having both syntactic and model theoretic aspects, with Petri nets and graph rewriting [BG95, MP95] Our goal in the second half of this paper is to develop the model theoretic approach, and to make precise connections to the annotated ....

....[Bed88, Shi85, WN95] This is precisely related to causal bisimulation [BS98] In CCS causal dependency arises from pre xing in the behaviour of the process x:y:0 the y output causally depends on the x output. In calculus, name binding introduces new dependencies, as thoroughly discussed in [DP99]. Transitions occurring in different parallel components of a process term, naively regarded as independent, may be forced to occur in a xed order. For example, in the process ( y) xy j yz) the transition yz can be observed only after xy before this occurs the new bound channel 2 is not known to ....

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P. Degano and C. Priami. Non-interleaving semantics for mobile processes. Theoretical Computer Science, 216(1-2):237270, 1999.

....i m 1 for c( w) in Pn . Then we have (i) for all i k , Delta i k does not contains either 0 nor k( v) ii) c( w) in Pn does not occur under replicators. Various kinds of communication causality in calculus were defined and studied based on parametric labelled transition systems, cf. [6, 11]. Our neededness between sequences of reduction relations ( actions) is, however, simply defined without introducing additional information on labelled transition systems and enough for the formalisation of several causal relations between combinators in this paper (see also x4.2) 3.6. Proofs ....

Degano, P. and Priami, C., Non-interleaving Semantics for Mobile Processes, Proc. of ICALP'95, LNCS 994, pp.660--671, Springer-Verlag, 1995.

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P. Degano and C. Priami. "Non Interleaving Semantics for Mobile Processes". Theoretical Computer Science, 216:237--270, 1999. 30

....of the calculus, in which constant definition is adopted for the specification of recursive processes. In order to accomplish that, we find it difficult to stick to the usual operational presentation of the operator, resorting instead to a proposal in [15] Then, we exploit the technique used in [7] to define non interleaving semantics for the r calculus [13] and we extend it to include the case of the replication operator, considering, for the sake of presentation, only pure ccs [tt] The essence of the enhanced sos semantics proposed in [7, 8] consists in encoding (portions of) the proof ....

.... in [15] Then, we exploit the technique used in [7] to define non interleaving semantics for the r calculus [13] and we extend it to include the case of the replication operator, considering, for the sake of presentation, only pure ccs [tt] The essence of the enhanced sos semantics proposed in [7, 8] consists in encoding (portions of) the proof of a transition in its label. The resulting labeled transition system is thus called proved. Enhanced labels are sufficient to derive a causal semantics of the calculus. In the next section we briefly define the proved operational semantics of ccs with ....

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P. Degano and C. Priami. Non interleaving semantics for mobile processes. Theoret. Cornput. Sci., 216:237-270, 1999.

....j(P3 jP4 ) right) branches of a tree of sequential processes denote the left (resp. right) component of parallel compositions, then label their arcs with tag jj 0 (resp. jj 1 ) Tecnically, relative addresses can be inductively built while deducing transitions, when a proved semantics is used [13, 12], in which labels of transitions encode (a portion of) their deduction tree. We recall the formal definition of relative addresses [5] Definition 1 (relative addresses) Let # i ; # i 2 fjj 0 ; jj 1 g , let be the empty string. Then, the set of relative addresses, ranged over by l, is ....

P. Degano and C. Priami. "Non Interleaving Semantics for Mobile Processes". Theoretical Computer Science, 216:237--270, 1999.

.... 0 # 0 , 1 # # 1 # 1 R (5) we can say that the first reaction causes the second one if # 0 # 0 is a prefix of # # 0 # # 0 or of # # 1 # # 1 (and similarly for # 1 # 1 ) This conditions reflects the nesting of actions in the specification (for a full account onn the definition see [1]) If there is no causal relation the two reactions can occour in any temporal order: they are independent. Although it o#ers a qualitative view of processes, causality seems to play a relevant role in understanding complex biochemical reactions. As a side effect, causal based representation of a ....

P. Degano and C. Priami. Non-interleaving semantics for mobile processes. Theoretical Computer Science, 216, 1-2:237--270, 1999.

....code by merging the two kind of descriptions. Note that the weaver is not a complex compiler, but some kind of linker as he strategies to satisfy properties of components (i.e. aspects) are defined by the programmer in the aspect language. We adopt the very concrete (SOS) proved transition system [9, 7] whose transitions are labelled by encodings of their proofs. These enhanced labels allow us to handle locality. We use as a testbed the higher order calculus [17] enriched with a spawn operation to create new locations. We model a distributed process as a set of sequential processes collected ....

....where a name bound in includes Q in its scope [14] We enrich the labels of the standard interleaving transition system in order to encode more information. It is thus possible to derive different semantic models for our calculus by extracting new kinds of labels from the enriched ones [9]. We start with the definition of the enhanced labels. In addition, we introduce a function ( that takes an enhanced label to the corresponding standard action label. We report here a slight modification of the enhanced labels of [9] in which we also record the name of the agent identifiers and ....

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P. Degano and C. Priami. Non-interleaving semantics for mobile processes. Theoretical Computer Science, 216:237--270, 1999.

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P. Degano and C. Priami. "Non Interleaving Semantics for Mobile Processes". Theoretical Computer Science, 216:237--270, 1999. 16

....G, S, and R. The result of the composition of the relative addresses of S w.r.t. R and of G w.r.t. S is represented by the solid arrows. 4 Proved semantics Relative addresses can be inductively built while deducing transitions, when a proved semantics is used [9] In this section, we recall from [10] the proved transition system for the calculus, in which labels of transitions encode (a portion of) their deduction tree. The arrows of the proved transition system are labelled by #, where is an action and # is a string of jj 0 ; jj 1 , used to single out the sub process that actually ....

P. Degano and C. Priami. "Non Interleaving Semantics for Mobile Processes". Theoretical Computer Science, 216:237--270, 1999. 30

....transitions are labelled by encodings of their proofs. This very concrete representation of process behaviour was used to describe qualitative and quantitative non interleaving aspects of a variety of calculi, e.g. for the calculus [26] a calculus based on naming fairly more complex than ccs [14]. Indeed, simple relabellings of proved computations yield the main semantics presented in the literature, in particular the (interleaving and the) causal one which is of main interest here. It will be clear that enhanced labels and proof terms share the same algebraic structure, because the ....

....and concurrency relations between actions. From this relabelling, it is straightforward to recover the more standard representation of causality as a partial ordering of events, and that of concurrency. Both notions coincide with those de ned in the literature, as shown e.g. in [3,8] See [14] for a study of several non interleaving relations carried on the calculus, a fairly more expressive process algebra. Roughly, a transition # causally depends on a previous transition # 0 0 if (# 0 0 ) is a pre x of (# ) similarly when one of the transitions is a communication. ....

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P. Degano and C. Priami. Non interleaving semantics for mobile processes. Theoret. Comput. Sci., 216:237-270, 1999.

....requires non trivial adjustments to the existing causal semantics. This is because of the additional synchronization mentioned above that precedes and implicitly causes all the subsequent actions of the P process, thus falsifying the equation P = P j P . We exploit here the technique used in [6] to de ne a few non interleaving semantics for the calculus [10] and we extend it to the case of the operator. For the sake of presentation, we only consider pure CCS [8] with replication; the extension to the calculus is straightforward, following [6] The essence of the enhanced SOS ....

..... We exploit here the technique used in [6] to de ne a few non interleaving semantics for the calculus [10] and we extend it to the case of the operator. For the sake of presentation, we only consider pure CCS [8] with replication; the extension to the calculus is straightforward, following [6]. The essence of the enhanced SOS semantics proposed in [6] consists in encoding (portions of) the proof of a transition in its label. The resulting labelled transition system is thus called proved. Enhanced labels are sucient to derive a causal (and other non interleaving) semantics of the ....

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P. Degano and C. Priami. Non interleaving semantics for mobile processes. Theoret. Comput. Sci., 216:237-270, 1999. 16

....computation if and only if they form a concurrency diamond in pts (eventually, modulo = that is, we lift the notion of concurrency from one, or some computations to the whole transition system. We omit here the precise statement of this theorem, and refer the interested reader to Theorem 6. 4 of [10]. An immediate consequence is that we feel free to call equivalent (w.r.t. concurrency) computations and 0 that only differ in the order in which concurrent transitions occur, in symbols i 0 ; disregarding the actual identity of the processes involved (since Lemma 2.4 assures that the two ....

P. Degano and C. Priami. Non interleaving semantics for mobile processes. Extended abstract. In Automata, Languages and Programming, volume 944 of LNCS, pages 660--671. Springer Verlag, 1995.

....at the outset stage of a project. We start from an enhanced operational semantic of p calculus [15] in which the labels of transitions, besides the action, encode (in so called proof term) their derivation, according to the axioms and inference rules that define the semantics in the style of [6, 9]. Then, we provide a way to derive stochastic information This work has been partially supported by progetto TOSCA cofinanziato MURST. 1 2 Proceedings in Informatics of transitions by relabelling the enhanced labels. Following [16] we interpret the encoding of the derivation of a transition as ....

....free and bound names, are as usual; they are computed by functions fn, bn and n, respectively. We define the structural congruence j on processes as the least congruence equating a equivalent processes, and exchanging name binders n, i.e. nx) ny)P j (ny) nx)P. We define our enhanced labels as in [8, 6, 9]. The label of a transition records the inference rules used during its deduction, besides the action itself. Such an encoding is called proof term. Finally, we introduce a function that takes an enhanced label to the corresponding standard action label. Definition 2 Let L = fk 0 ; k 1 g with c ....

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DEGANO, P., AND PRIAMI, C. Non interleaving semantics for mobile processes. Theoretical Computer Science, 216 (1999), 237--270.

....and 1 (a; r) Instead the process (a; r) originates a single transition that leads to 0 and that is labelled (a; r) Similarly, we record the applications of rules Par i with jj 0 and jj 1 tags. We start with the definition of the alphabet for the labels of transitions, that we call proof terms [2, 5]. The string prefixing the label of any transition is an encoding of (a portion of) its derivation tree. Functions and extract actions and rates from proof terms, respectively. Definition 2.4 Let # 2 fjj 0 ; jj 1 ; 0 ; 1 g . Proof terms (with metavariable ) are defined by the following ....

P. Degano and C. Priami. Non interleaving semantics for mobile processes. Theoretical Computer Science, 216:237--270, 1999.

....As a consequence, our model can easily be transferred to real programming languages, such as Facile [14, 28] or CML [19, 24] Roughly speaking, we define a distributed version of the calculus as far as data are concerned. The last two authors addressed the issue of non centralized control in [12]. The two proposals can be merged, yielding a fully non interleaving description of the calculus and of other languages for mobility. We hope that our proposal might aid the design of language implementations, by suggesting how these can be made truly concurrent. The paper is organized as ....

....R be P 1 . The address of P 3 relative to P 1 is jj 0 jj 1 ffljj 1 jj 1 jj 0 (read the path upwards from P 1 to the root and reverse, then downwards to P 3 ) We will inductively build relative addresses while deducing transitions. We use the transition system of the calculus introduced in [12]. It suffices to record the application of inference rules involving the j in the label of a deduced transition. A slightly more complex situation arises when a process receives a name and sends it to another process. The name must arrive at the new receiver with the address of the generator (not ....

[Article contains additional citation context not shown here]

P. Degano and C. Priami. Non interleaving semantics for mobile processes. Extended abstract. In Proceedings of ICALP'95, LNCS 944, pages 660--671. Springer-Verlag, 1995. To appear in TCS.

No context found.

P. Degano and C. Priami. Non-interleaving semantics for mobile processes. Theoretical Computer Science, 216(1-2):237270, 1999.

No context found.

Degano, P., and C. Priami. 1999. "Non Interleaving Semantics for Mobile Processes ". Theoretical Computer Science 216:237--270.

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