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23
Delegation Logic: A Logicbased Approach to Distributed Authorization
 ACM Transactions on Information and System Security
, 2000
"... We address the problem of authorization in largescale, open... ..."
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Cited by 200 (13 self)
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We address the problem of authorization in largescale, open...
Finite Representation of Infinite Query Answers
, 1992
"... : We define here a formal notion of finite representation of infinite query answers in logic programs. We apply this notion to Datalog nS (Datalog with n successors): an extension of Datalog capable of representing infinite phenomena like flow of time or plan construction. Predicates in Datalog nS ..."
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Cited by 30 (5 self)
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: We define here a formal notion of finite representation of infinite query answers in logic programs. We apply this notion to Datalog nS (Datalog with n successors): an extension of Datalog capable of representing infinite phenomena like flow of time or plan construction. Predicates in Datalog nS can have arbitrary unary and limited nary function symbols in one fixed position. This class of logic programs is known to be decidable. However, least Herbrand models of Datalog nS programs may be infinite and consequently queries may have infinite answers. We present a method to finitely represent infinite least Herbrand models of Datalog nS programs as relational specifications. A relational specification consists of a finite set of facts and a finitely specified congruence relation. A relational specification has the following desirable properties. First, it is explicit in the sense that once it is computed, the original Datalog nS program (and its underlying computational engine) can ...
Observational Proofs with Critical Contexts
 In Fundamental Approaches to Software Engineering
, 1998
"... Observability concepts contribute to a better understanding of software correctness. In order to prove observational properties, the concept of Context Induction has been developed by Hennicker [10]. We propose in this paper to embed Context Induction in the implicit induction framework of [8]. The ..."
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Cited by 24 (3 self)
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Observability concepts contribute to a better understanding of software correctness. In order to prove observational properties, the concept of Context Induction has been developed by Hennicker [10]. We propose in this paper to embed Context Induction in the implicit induction framework of [8]. The proof system we obtain applies to conditional specifications. It allows for many rewriting techniques and for the refutation of false observational conjectures. Under reasonable assumptions our method is refutationally complete, i.e. it can refute any conjecture which is not observationally valid. Moreover this proof system is operational: it has been implemented within the Spike prover and interesting computer experiments are reported.
Combining and Representing Logical Systems Using ModelTheoretic Parchments
 In Recent Trends in Algebraic Development Techniques, volume 1376 of LNCS
, 1997
"... . The paper addresses important problems of building complex logical systems and their representations in universal logics in a systematic way. We adopt the modeltheoretic view of logic as captured in the notions of institution and of parchment (an algebraic way of presenting institutions). We prop ..."
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Cited by 15 (4 self)
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. The paper addresses important problems of building complex logical systems and their representations in universal logics in a systematic way. We adopt the modeltheoretic view of logic as captured in the notions of institution and of parchment (an algebraic way of presenting institutions). We propose a new, modified notion of parchment together with parchment morphisms and representations. In contrast to the original parchment definition and our earlier work, in modeltheoretic parchments introduced here the universal semantic structure is distributed over individual signatures and models. We lift formal properties of the categories of institutions and their representations to this level: the category of modeltheoretic parchments is complete, and their representations may be put together using categorical limits as well. However, modeltheoretic parchments provide a more adequate framework for systematic combination of logical systems than institutions. We indicate how the necessar...
Inductive Theorem Proving for Design Specifications
 J. Symbolic Computation
, 1997
"... We present a number of new results on inductive theorem proving for design specifications based on Horn logic with equality. Induction is explicit here because induction orderings are supposed to be part of the specification. We show how the automatic support for program verification is enhanced i ..."
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Cited by 12 (9 self)
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We present a number of new results on inductive theorem proving for design specifications based on Horn logic with equality. Induction is explicit here because induction orderings are supposed to be part of the specification. We show how the automatic support for program verification is enhanced if the specification satisfies a bunch of rewrite properties, summarized under the notion of canonicity. The enhancement is due to inference rules and corresponding strategies whose soundness is implied by the specification's canonicity. The second main result of the paper provides a method for proving canonicity by using the same rules, which are applied in proofs of conjectures about the specification and the functionallogic programs it contains. Contents 1 Introduction 2 1.1 Expander . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 Proof by term rewriting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
The ruleml family of web rule languages
 In 4th Int. Workshop on Principles and Practice of Semantic Web Reasoning
, 2006
"... harold.boley AT nrc DOT gc DOT ca Abstract. The RuleML family of Web rule languages contains derivation (deduction) rule languages, which themselves have a webized Datalog language as their inner core. Datalog RuleML’s atomic formulas can be (un)keyed and (un)ordered. Inheriting the Datalog features ..."
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Cited by 10 (5 self)
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harold.boley AT nrc DOT gc DOT ca Abstract. The RuleML family of Web rule languages contains derivation (deduction) rule languages, which themselves have a webized Datalog language as their inner core. Datalog RuleML’s atomic formulas can be (un)keyed and (un)ordered. Inheriting the Datalog features, Hornlog RuleML adds functional expressions as terms. In Hornlog with equality, such uninterpreted (constructorlike) functions are complemented by interpreted (equationdefined) functions. These are described by further orthogonal dimensions “single vs. setvalued ” and “first vs. higherorder”. Combined modal logics apply special relations as operators to atoms with an uninterpreted relation, complementing the usual interpreted ones. 1
Modular Swinging Types
, 1999
"... . Swinging types [18] provide an integrated framework for specifying software on the basis of manysorted logic in terms of "static" functions and relations as well as "dynamic" transition systems. Swinging types combine equational, Horn and modal logic for the purpose of using evaluation and pr ..."
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Cited by 8 (8 self)
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. Swinging types [18] provide an integrated framework for specifying software on the basis of manysorted logic in terms of "static" functions and relations as well as "dynamic" transition systems. Swinging types combine equational, Horn and modal logic for the purpose of using evaluation and proof rules from all three logics for rapid prototyping and verification. A swinging specification separates from each other visible sorts that denote domains of data identified by their structure; hidden sorts that denote domains of data identified by their behavior in response to observers; predicates (least relations) that represent inductive (ly provable) properties; and predicates (greatest relations) that represent complementary "coinductive" properties. The paper at hand deals with structured specifications with swinging components. Vertical structuring is supported by a deductionoriented refinement criterion that admits, for instance, to implement visible sorts by hidden s...
Representations, Hierarchies, and Graphs of Institutions
, 1996
"... For the specification of abstract data types, quite a number of logical systems have been developed. In this work, we will try to give an overview over this variety. As a prerequisite, we first study notions of {\em representation} and embedding between logical systems, which are formalized as {\em ..."
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Cited by 5 (4 self)
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For the specification of abstract data types, quite a number of logical systems have been developed. In this work, we will try to give an overview over this variety. As a prerequisite, we first study notions of {\em representation} and embedding between logical systems, which are formalized as {\em institutions} here. Different kinds of representations will lead to a looser or tighter connection of the institutions, with more or less good possibilities of faithfully embedding the semantics and of reusing proof support. In the second part, we then perform a detailed ``empirical'' study of the relations among various wellknown institutions of total, ordersorted and partial algebras and firstorder structures (all with Horn style, i.e.\ universally quantified conditional, axioms). We thus obtain a {\em graph} of institutions, with different kinds of edges according to the different kinds of representations between institutions studied in the first part. We also prove some separation results, leading to a {\em hierarchy} of institutions, which in turn naturally leads to five subgraphs of the above graph of institutions. They correspond to five different levels of expressiveness in the hierarchy, which can be characterized by different kinds of conditional generation principles. We introduce a systematic notation for institutions of total, ordersorted and partial algebras and firstorder structures. The notation closely follows the combination of features that are present in the respective institution. This raises the question whether these combinations of features can be made mathematically precise in some way. In the third part, we therefore study the combination of institutions with the help of socalled parchments (which are certain algebraic presentations of institutions) and parchment morphisms. The present book is a revised version of the author's thesis, where a number of mathematical problems (pointed out by Andrzej Tarlecki) and a number of misuses of the English language (pointed out by Bernd KriegBr\"uckner) have been corrected. Also, the syntax of specifications has been adopted to that of the recently developed Common Algebraic Specification Language {\sc Casl} \cite{CASL/Summary,Mosses97TAPSOFT}.
A System for Testing and Verifying FunctionalLogic Programs
, 2002
"... Contents 1 A uniform proof method 3 2 Design language 4 2.1 Syntax and semantics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Types and traits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Sample specifi ..."
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Cited by 5 (4 self)
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Contents 1 A uniform proof method 3 2 Design language 4 2.1 Syntax and semantics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2.2 Types and traits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 2.3 Sample specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3.1 Even and odd . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3.2 Less or equal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.3.3 Mergesort . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 2.3.4 Replace by minimum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.3.5 Find paths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.3.6 Mutual exclusion . . . . . . . . . . . . . . . . . . . . .
Inductive Theorem Proving for Algebraic Specifications  TIP System User's Manual
, 1994
"... This manual introduces an inductive theorem prover called TIP system (Term Induction Prover). This prover can be used to verify universally quantified systems of conditional equations over algebraic specifications. The proofs can be done in either an interactive or an automatic way. The reader learn ..."
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This manual introduces an inductive theorem prover called TIP system (Term Induction Prover). This prover can be used to verify universally quantified systems of conditional equations over algebraic specifications. The proofs can be done in either an interactive or an automatic way. The reader learns how to use the TIP system, especially how to do inductive proofs in an interactive way. Besides, the internal proof algorithm and the builtin heuristics are explained and some useful techniques for successful theorem proving are presented. Preface This report refers to the TIP system version 3.0. Older versions may not have all the features described in this manual or may behave in a slightly different way than described in this manual. For more information on the distribution of the TIP system, error reports, suggestions, etc. please send electronic mail to fraus@forwiss.unipassau.de. If you would like to get and install the prover on your machine(s) then please see appendix B. Thank...