## Nonexpressibility of Fairness and Signaling (1990)

Venue: | in "Proceedings, IEEE Foundations of Computer Science", Panangaden |

Citations: | 4 - 1 self |

### BibTeX

@INPROCEEDINGS{Mcallester90nonexpressibilityof,

author = {David Mcallester and Prakash Panangaden and Vasant Shanbhogue},

title = {Nonexpressibility of Fairness and Signaling},

booktitle = {in "Proceedings, IEEE Foundations of Computer Science", Panangaden},

year = {1990},

pages = {99--131}

}

### OpenURL

### Abstract

In this paper we establish new expressiveness results for indeterminate dataflow primitives. We consider split primitives with three differing fairness assumptions and show that they are strictly inequivalent in expressive power. We also show that the ability to announce internal choices enhances the expressive power of two of the primitives. These results are proved using a very crude notion of observation and thus apply in any reasonable theory of process equivalence. 1 Introduction Fairness is regarded as an important property of real systems and there is considerable interest in semantic theories and proof systems for reasoning about fairness [12]. In the present paper we examine the relative expressive power of a variety of fairness primitives and prove new inexpressibility results in the context of asynchronous systems. We prove that three different "split" primitives have different expressive power. We also consider the effect of adding signaling to each primitive. By "signalin...

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Citation Context ...tworks, i.e. networks whose structure remains fixed throughout execution. Our interest in this work stemmed from earlier discoveries by Panangaden and Stark [25, 26, 28] that the fair merge primitive =-=[18] is strict-=-ly "more powerful" than other primitives exhibiting unbounded indeterminacy or countable indeterminacy. This showed that one could not classify indeterminate primitives on the degree of bran... |

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Citation Context ...ould not classify indeterminate primitives on the degree of branching they embodied. All fair systems include primitives with countable indeterminacy [11]. In the programming model studied by Chandra =-=[4, 11]-=-, countable indeterminacy and fairness are equivalent. In the case of asynchronous dataflow networks [16], the analysis is complicated by the fact that a process may receive data from different autono... |

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Citation Context ...ated" to implement SS. The second interesting result is that we cannot simulate signals except when we have strong 3 fairness. This result is related to sequentiality in the sense of Kahn and Plo=-=tkin [8, 17]-=-; but we do not have a theory of sequential indeterminate processes. 2 Traces of Dataflow Networks In this paper we work with traces of dataflow networks. These are abstractions of computation sequenc... |

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