B. Victor. The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes. PhD thesis, Department of Computer Systems, Uppsala University, 1998.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....xy. Here, triggers t 1 , t 2 , t 3 guard each input and output command, and also transport the entire environment to every continuation. An encoded term could then be executed directly on the distributed channel machine. The second encoding is based upon the fusion calculus of Parrow and Victor [12], a calculus in which the input command u#y.P is not binding. The encoding [10] uses the sub calculus with only solos u x and u x. It uses the reaction relation (#z) u u#y R) R# where every equivalence class generated by x = y has exactly one element not z, and the ....

....prototype implementation by Wischik [19] and in projects by students at the University of Bologna. With respect to the close correspondence with pilike calculi, we have proved abstraction results which are stronger than those obtained for other implementations. On the contrary, the fusion calculus [12] and the solos calculus [10] are awkward to implement in the fusion machine, even though they are closely related to the explicit fusion calculus. This is because they only allow reaction after a global search for restricted names. We are currently working on a full distributed implementation for ....

J. Parrow and B. Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In LICS'98, pages 176--185. IEEE, Computer Society Press.

....becomes more symmetrical: symmetric action calculi have a discrete monoid comonoid structure. This means that they are also compact closed (see Chapter 2) and therefore more similar in structure to interaction categories than the standard action calculi. There is an analogy to the fusion calculus [PV98], which tries to resolve the asymmetry between input and output actions in the p calculus. 3.3 A Categorical Type System for CCS like Languages 3.3.1 Motivation We would like to define a category of processes in a language like CCS, along the lines of the models in the previous section: types ....

....of CCS, without restriction. From this process algebra we build a symmetric monoidal co fibration, as required in the construction of Proc. We then extend the process algebra CCS by adding constructors for restriction, and for identification of names, similar to fusions in the fusion calculus [PV98], to obtain a process algebra which we call FCCS. From this latter process algebra, we will then construct a syntactic category, and show that it has the same categorical structure as Proc. We provide translations between the syntactic category, and the instance of Proc, and show that they yield ....

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Joachim Parrow and Bjrn Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In Proc. LICS, 1998.

....that only one process holds a read capability of a logical variable [46] in which case ask can destroy a message it has received, as will be discussed in detail in this paper. One feature of constraint based concurrency included into name based concurrency only recently by the Fusion calculus [48] is that two channels can be fused into a single channel. 2.4 Locality in Global Store The notion of shared, global store provided by CCP must be understood with care. Unlike conventional shared memory multiprocessing, constraint store of CCP is highly structured and localized. All channels in ....

....escape through Y. Rather, we want to allocate and garbage collect them locally and let Y emit an integer constant. 9 Related Work Relating the family of # calculi and the CCP formalism has been done as proposals of calculi such as the # calculus [33] the # calculus [24] and the Fusion calculus [48], all of which incorporate constraints (or name equation) in some form. The # calculus is unique in that it uses procedures with encapsulated states to model concurrency and communication rather than the other way around. The # calculus introduces constraints into name based concurrency, while ....

Victor, B., The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes, PhD Thesis, Uppsala Univ., 1998.

....its process algebraic formulation. Two of its innovations are adopted in the present work; the unconstrained connectivity of the kind mentioned above, and the explicit fusions here called aliases and coaliases of Gardner and Wischik [11] developed from the fusion calculus of Parrow and Victor [25]. These authors are further developing a calculus of fusion graphs. 3) It may be argued that to allow arcs to link nodes which are distant cousins, i.e. enclosed within distinct parent nodes arbitrarily far apart in the nesting structure, is contrary to reality. But we wish to model not only the ....

....controls are again atomic. In the first and third rules the reactum has a link which makes an alias for . Such an alias is essentially an explicit fusion in the sense of Gardner and Wischik [11] their calculus of explicit fusions was developed from the fusion calculus of Parrow and Victor [25] and from action calculi [22] and has guided the present development. The reactum in the second rule, and the redex in the third rule, both illustrate the use of a closed (i.e. unnamed) edge respectively between the = A B B nodes and between the C D BFEHG I DFJ BFEKG AI ....

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Parrow, J. and Victor, B. (1998), The fusion calculus: expressiveness and symmetry in mobile processes. Proc. LICS'98, IEEE Computer Society Press.

....to u, and w(z) P deployed to w. The result is that the large continuations are already placed at their correct locations; all that is needed is a small message to trigger them. Technically, we have shown elsewhere [2] how the triggers can be encoded in a version of the pi calculus with fusions [3, 7]. A fusion makes two channels become equivalent, in the sense that a message sent to either will have the same effect) Our machine therefore implements this fusion version of the calculus, rather than the pure pi calculus, and we leave pre deployment as a compiletime optimisation. Note that in ....

J. Parrow and B. Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In LICS'98, pages 176--185. Computer Society Press.

....We start by brie y recalling the fusion calculus, then we de ne an inductive translation of fusion processes into terms and eventually we prove that the translation preserves transitions. We report here the reduction semantics for the recursion free fragment of the guarded fusion calculus from [14] whose syntax in BNF like style is P : 0 j :P 0 :Q j P 1 jP 2 j (x)P with ; 0 being either u x for the input or u x for the output. Note that the objects x of input actions are not bound by the input pre x in the process pre xed as instead happens in the calculus [7] The only ....

.... The structural congruence in the rule Str is the smallest congruence on processes satisfying: F ; 0) and (F ; j = 0) are commutative monoids; z)0 0, x) y)P (y) x)P , x) P Q) x)P (x)Q; x)P jQ (x) P jQ) if x 62 fn(Q) Finally note that fusion pre xes as f y = xg:P [14] can be viewed as derived forms for processes as (u) u x:0ju y:P ) with u a fresh name. We start with a function [ that maps fusion processes into terms. De nition 7. Let [ F T be de ned by structural induction as [ 0] 0 [ x u:P ] x u:P ] x u) P ] P jQ] ....

Bjorn Victor. The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes. PhD thesis, Dept. of Computer Science, Uppsala University, 1998.

....functions and arguments is lost. Indeed a computation is possible when two objects interact and evolve generating other interaction or modifying their environments via substitutions. We also address the issue of encoding concurrent computations by showing as an example how the fusion calculus [9] (and hence [7] 10] and [8] calculi) can be expressed in our formalism. Finally we propose an encoding of proof nets in the calculus and we introduce the question of typing in relation with linear logic. The paper is organized as follows. In the next section we introduce the basic ....

....X;B [ x]fj ( u]fj u ta ; a jg x ) v]fj v tb ; b jg x ) jg X;A u B Table 3. Additive fragment. 5 Concurrency In this section we show how concurrent computations are included into calculus computations by providing an encoding of the fusion calculus [9] into our calculus. We start by brie y recalling the fusion calculus, then we de ne an inductive translation of fusion processes into terms and eventually we prove that the translation preserves transitions. We report here the reduction semantics for the recursion free fragment of the guarded ....

Joachim Parrow and Bjorn Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In Proceedings of LICS '98, pages 176-185. IEEE, Computer Society Press, June 1998.

....final graph of the rewriting by merging the corresponding nodes. As is done in calculus, we allow to merge new nodes with other nodes (new or old) Merging among already existing nodes is not allowed. Relaxing this constraint, would permit fusions of nodes in the style of the fusion calculus [7]. Instead, in [2] we consider a syntactic restriction of our formalisms in which we allow merging new nodes only, in the style of the I calculus [6] These policies of which nodes are shared are independent of the synchronization mechanisms applied. To formalize synchronized rewriting we use, as ....

Victor, B. The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes. PhD thesis, Uppsala University, 1998.

....Q = xy: xy:0. Only one transition is incident out of the abstract state corresponding to Q, while two of them are incident out of the abstract state for P , one for the case y = x and one for all the remaining values of y. Symmetric handling of input and output is a goal of the fusion calculus [26]. Notice that the states of the nal model in Coalg form a algebra. So, in particular, a support supp(X) is de ned for each of these states. The support of a calculus agent in lts de nes the free names of the agent; the support of the corresponding state in the nal model, instead, de ne ....

J. Parrow and B. Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In Proc. LICS'98, IEEE. Computer Society Press, 1998.

....: A1 #A2 (Seal Algo) # ## x : Id A # ## P : A # # ## x [P ] A # # A 4 This is due to the specificity of the receive action: when a seal is received it is activated at the same level as the process that received it. The movement actions look like interactions in the Fusion Calculus [14]. 4.4 Properties The typing algorithm defined above is sound and complete with respect to the type system. Theorem 1 (Soundness and completeness) 1. If # ## P : A then # ## P : A. 2. If # ## P : A then #A # such that A # # A and # ## P : A # . A corollary of this theorem is the ....

J. Parrow and B. Victor. The Fusion Calculus: Expressiveness and symmetry in mobile processes. In Logic in Computer Science. IEEE Computer Society Press, 1998.

....much of it is really necessary in order to attain the expressive power. This has led to several interesting and expressive subcalculi. For example, in the more easily implemented asynchronous subcalculus [2, 8] the output pre x u v : P is replaced by the output particle u v. In the fusion calculus [19] the reduction of an input and output results in a fusion of names rather than a substitution. In that calculus both input and output pre x can be replaced by their corresponding particles, in other words, there is no need for explicit representation of temporal precedence. These particles are ....

....P P 0 Side conditions in the rst rule: jexj = jeyj; agrees with fex = e yg; ran( e z = and dom( e z: Fig. 4. Reduction rules for the calculus of solos. set. The free names in P , denoted fn(P ) are the names in P with a non bound occurrence. The (choice free) fusion calculus [19] consists of the above agents and those formed using the pre x operator, namely agents of the form : P . Operational semantics. We begin by de ning a structural congruence which equates all agents we will never want to distinguish for any semantic reason, and then use this when giving the ....

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J. Parrow and B. Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In Proc. of LICS '98, pages 176-185. IEEE, Computer Society Press, July 1998.

No context found.

B. Victor. The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes. PhD thesis, Department of Computer Systems, Uppsala University, 1998.

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J. Parrow and B. Victor. The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes. In Proc. of LICS'98. IEEE Computer Society Press, 1998.

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Parrow, J. and Victor, B. (1998), The fusion calculus: expressiveness and symmetry in mobile processes. Proc. LICS'98, IEEE Computer Society Press.

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B. Victor. The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes. PhD thesis, Department of Computer Systems, Uppsala University, 1998.

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Parrow, J. and Victor, B. (1998), The fusion calculus: expressiveness and symmetry in mobile processes. Proc. LICS'98, IEEE Computer Society Press.

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J. Parrow and B. Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In Thirteenth Annual Symposium on Logic in Computer Science (LICS 1998), pages 176--185. IEEE, IEEE Computer Society, 1998.

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Joachim Parrow and Bjorn Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In Proceedings of LICS'98, 1998. 25

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Parrow, J. and Victor, B. (1998), The fusion calculus: expressiveness and symmetry in mobile processes. Proc. LICS'98, IEEE Computer Society Press.

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J. Parrow and B. Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In Proc. LICS'98, IEEE Computer Society Press, 1998.

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Bjorn Victor. The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes. PhD thesis, Dept. of Computer Systems, Uppsala University, Sweden, June 1998.

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Joachim Parrow and Bjorn Victor. The Fusion Calculus: Expressiveness and symmetry in mobile processes. In Proceedings of LICS '98 [IEE98], pages 176{ 185.

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B. Victor. The Fusion Calculus : Expressiveness and Symmetry in Mobile Processes, Phd Dissertation, Department of Computer Science, Uppsala University, June 1998.

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J. Parrow and B. Victor. The Fusion Calculus: Expressiveness and Symmetry in Mobile Processes(extended abstract), Poceedings of the LICS'98, 21-24 June 1998, Indianapolis.

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Joachim Parrow and Bjorn Victor. The fusion calculus: Expressiveness and symmetry in mobile processes. In Proceedings of LICS '98, 1998.

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