Deng, Yuxin (2005) Axiomatisations and Types for Probabilistic and Mobile Processes. PhD thesis Informatique Temps Réel, Robotique et Automatique, ENSMP - CMA Centre de Mathématiques Appliquées, ENSMP.
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Abstract
The focus of this thesis are the theoretical foundations for reasoning about algorithms and protocols for modern distributed systems. Two important features of models for these systems are probability and typed mobility: probabilities can be used to quantify unreliable or unpredictable behaviour and types can be used to guarantee secure behaviour in systems with a mobile structure. In this thesis we develop algebraic and type-based techniques for behavioural reasoning on probabilistic and mobile processes. In the first part of the thesis we study the algebraic theory of a process calculus which combines both nondeterministic and probabilistic behaviour in the style of Segala and Lynch's probabilistic automata. We consider various strong and weak behavioural equivalences, and we provide complete axiomatisations for finite-state processes, restricted to guarded recursion in the case of the weak equivalences. In the second part of the thesis we investigate the algebraic theory of the n-calculus under the effect of capability types, which are one of the most useful forms of types in mobile process calculi. Capability types allow one to distinguish between the capability to read from a channel, to write to a channel, and to both read and write. They also give rise to a natural and powerful subtyping relation. We consider two variants of typed bisimilarity, both in their late and in their early version. For both of them, we give complete axiomatisations on the closed finite terms. For one of the two variants, we provide a complete axiomatisation for the open finite terms. In the last part of the thesis we develop a type-based technique for verifying the termination property of some mobile processes. We provide four type systems to guarantee this property. The type systems are obtained by successive refinements of the types of the simply typed n-calculus. The termination proofs take advantage of techniques from term rewriting systems. These type systems can be used for reasoning about the terminating behaviour of some non-trivial examples: the encodings of primitive recursive functions, the protocol for encoding separate choice in terms of parallel composition, a symbol table implemented as a dynamic chain of cells. These results lay out the foundations for further study of more advanced models which may combine probabilities with types. They also highlight the robustness of the algebraic and typebased techniques for behavioural reasoning.
| Item Type: | PhD Thesis (PhD) |
|---|---|
| Thesis Supervisor: | Sangiorgi, Davide |
| Date: | July 2005 |
| Board of examiners: | Kesner, Delia and Hennessy, Matthew and Segala, Roberto and Di cosmo, Roberto |
| Discipline: | Informatique Temps Réel, Robotique et Automatique |
| Collection (Fonds): | ENSMP |
| Institution: | ENSMP |
| Department: | ENSMP - CMA Centre de Mathématiques Appliquées |
| Subjects: | 2. Information and Communication Sciences and Technologies |
| Uncontrolled Keywords: | Axiomatisation, Probabilistic process, Mobile process, Process calculi, Axiomatisation, Processus probabiliste, Processus mobile, Calcul processus |
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Table of content
Contents
Abstract
Acknowledgements
Main Notations
R´esum´e en fran¸cais
1 Introduction
1.1 Background
1.2 Objectives
1.3 Axiomatisations for Probabilistic Processes
1.4 Axiomatisations for Typed Mobile Processes
1.5 Termination of Mobile Processes by Typability
1.6 Outline of the Thesis
2 Preliminaries
2.1 A Calculus of Communicating Systems
2.2 The n-calculus
2.2.1 From CCS to the n-calculus
2.2.2 The Untyped n-calculus
2.2.3 Sorts and Sorting
2.2.4 A Simple Example
2.2.5 The Simply Typed n-calculus
2.2.6 Subtyping
3 Axiomatisations for Probabilistic Processes
3.1 Probabilistic Distributions
3.2 A Probabilistic Process Calculus
3.3 Behavioural Equivalences
3.3.1 Equivalence of Distributions
3.3.2 Behavioural Equivalences
3.3.3 Probabilistic "Bisimulation up to" Techniques
3.3.4 Some Properties of Strong Bisimilarity
3.3.5 Some Properties of Observational Equivalence
3.4 Axiomatisations for All Expressions
3.4.1 Axiomatizing Strong Bisimilarity
3.4.2 Axiomatizing Strong Probabilistic Bisimilarity
3.5 Axiomatisations for Guarded Expressions
3.5.1 Axiomatizing Divergency-Sensitive Equivalence
3.5.2 Axiomatizing Observational Equivalence
3.6 Axiomatisations for Finite Expressions
3.7 Summary
4 Axiomatisations for Typed Mobile Processes
4.1 A Fragment of The Typed n-calculus
4.1.1 Standard Operational Semantics
4.1.2 Typed Labelled Transition System
4.1.3 Typed Bisimilarity
4.2 Proof System for the Closed Terms
4.3 Axioms for Typed Bisimilarity
4.3.1 The Axiom System
4.3.2 Soundness and Completeness
4.4 Other Equivalences
4.4.1 Hennessy and Rathke's Typed Bisimilarity
4.4.2 Early Bisimilarity
4.5 Adding Parallelism
4.6 Summary
5 Termination of Mobile Processes by Typability
5.1 Preliminary Notations
5.2 The Core System: the Simply Typed n-calculus with Levels
5.3 Allowing Limited Forms of Recursive Inputs
5.3.1 The Type System
5.3.2 Example: Primitive Recursive Functions
5.4 Asynchronous Names
5.4.1 Proving Termination with Asynchronous Names
5.4.2 Example: the Protocol of Encoding Separate Choice
5.5 Partial Orders
5.5.1 The Type System
5.5.2 Example: Symbol Table
5.6 Summary
6 Conclusions and Future Work
A Proofs from Chapter 3
A.1 Proof of Lemma 3 - 14
A.2 Proof of Proposition 3 - 34
A.3 Proof of Lemma 3 - 36
A.4 Proof of Lemma 3 - 45
B Proofs from Chapter 4
B.1 Some More Derived Rules
B.2 Proof of Theorem 4 - 36
C Proofs from Chapter 5
C.1 Proofs from Section 5 - 2
C.2 Proofs from Section 5 - 3
C.3 Extending T 0 with Polyadicity and Conditional
C.4 Proofs from Section 5 - 4
C.5 Proofs from Section 5 - 5
C.6 Levels in the Join-calculus
Bibliography
| ID Code: | 1344 |
|---|---|
| Deposited By: | Brigitte HANOT |
| Deposited On: | 22 August 2005 |
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