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Embedding as a tool for Language Comparison
, 1994
"... This paper addresses the problem of defining a formal tool to compare the expressive power of different concurrent constraint languages. We refine the notion of embedding by adding some "reasonable" conditions, suitable for concurrent frameworks. The new notion, called modular embedding, i ..."
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Cited by 35 (5 self)
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This paper addresses the problem of defining a formal tool to compare the expressive power of different concurrent constraint languages. We refine the notion of embedding by adding some "reasonable" conditions, suitable for concurrent frameworks. The new notion, called modular embedding, is used to define a preorder among these languages, representing different degrees of expressiveness. We show that this preorder is not trivial (i.e. it does not collapse into one equivalence class) by proving that Flat CP cannot be embedded into Flat GHC, and that Flat GHC cannot be embedded into a language without communication primitives in the guards, while the converses hold. 4 A; C; D; G; M;O;P;R; T : In calligraphic style. ss; ff ; dd: In slanted style. \Sigma; \Gamma; #; oe; ; /; ΓΈ; ff. S ; [; "; ;; 2 j=; 6j=; ; 9 +; k; ~ +; ~ k; ! \Gamma! W ; \Gamma! ; ; \Gamma! W ; \Gamma! ; h; i; [[; ]]; d; e ffi; ?; ; 5 All reasonable programming languages are equivalent, since they are Turing...
The expressive power of indeterminate dataflow primitives
 Information and Computation
, 1992
"... We analyze the relative expressive power of variants of the indeterminate fair merge operator in the context of static dataflow. We establish that there are three different, provably inequivalent, forms of unbounded indeterminacy. In particular, we show that the wellknown fair merge primitive canno ..."
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Cited by 17 (7 self)
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We analyze the relative expressive power of variants of the indeterminate fair merge operator in the context of static dataflow. We establish that there are three different, provably inequivalent, forms of unbounded indeterminacy. In particular, we show that the wellknown fair merge primitive cannot be expressed with just unbounded indeterminacy. Our proofs are based on a simple trace semantics and on identifying properties of the behaviors of networks that are invariant under network composition. The properties we consider in this paper are all generalizations of monotonicity. 1
A Denotational Framework forFair Communicating Processes
, 1996
"... For my parents, who refereed my earliest discourses on things (un)fair ..."
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On Impartiality
"... The fairness concept of impartiality is studied in the setting of shift coalgebras for two related comonads. With respect to the coproduct decompositions of dataflow connections, the impartial schedules are closed in the object of all schedules. The fairness concept of justice is derived from impart ..."
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The fairness concept of impartiality is studied in the setting of shift coalgebras for two related comonads. With respect to the coproduct decompositions of dataflow connections, the impartial schedules are closed in the object of all schedules. The fairness concept of justice is derived from impartiality. The impartial coalgebras for these two comonads appear to capture the essence of specifying impartiality and justice. The characterization of impartiality here emphasizes the extensive properties of fair merge as well as giving algebraic and geometric properties for the construction of new impartial mergers out of old. Research supported in part by National Science Foundation grant CCR8801886 and an Australian Research Council grant. 0 Introduction Impartiality and justice are specifications of properties about future events. Such properties often receive precise discussion as coalgebras. In the case of impartiality these coalgebras are even coalgebras for certain comonads. By ...