Efficient Decision Procedures for Message Deducibility and Static Equivalence

Computing knowledge in equational extensions of subterm convergent theories

Mathematical Structures in Computer Science ◽

10.1017/s0960129520000031 ◽

2020 ◽

Vol 30 (6) ◽

pp. 683-709

Author(s):

Serdar Erbatur ◽

Andrew M. Marshall ◽

Christophe Ringeissen

Keyword(s):

General Procedure ◽

Security Protocols ◽

Equational Theory ◽

Finite Measure ◽

Decision Procedures ◽

Rewrite Systems ◽

Static Equivalence ◽

Equivalence Problems ◽

Rewrite System

AbstractWe study decision procedures for two knowledge problems critical to the verification of security protocols, namely the intruder deduction and the static equivalence problems. These problems can be related to particular forms of context matching and context unification. Both problems are defined with respect to an equational theory and are known to be decidable when the equational theory is given by a subterm convergent term rewrite system (TRS). In this work, we extend this to consider a subterm convergent TRS defined modulo an equational theory, like Commutativity. We present two pairs of solutions for these important problems. The first solves the deduction and static equivalence problems in rewrite systems modulo shallow theories such as Commutativity. The second provides a general procedure that solves the deduction and static equivalence problems in subterm convergent systems modulo syntactic permutative theories, provided a finite measure is ensured. Several examples of such theories are also given.

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Interval logics and their decision procedures Part II: A real-time interval logic

Theoretical Computer Science ◽

10.1016/s0304-3975(96)00255-1 ◽

1996 ◽

Vol 170 (1-2) ◽

pp. 1-46 ◽

Cited By ~ 4

Author(s):

Y Ramakrishna

Keyword(s):

Real Time ◽

Decision Procedures ◽

Time Interval ◽

Interval Logic

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Monotonic and Non-Monotonic Logics of Knowledge1

Fundamenta Informaticae ◽

10.3233/fi-1991-153-405 ◽

1991 ◽

Vol 15 (3-4) ◽

pp. 255-274

Author(s):

Rohit Parikh

Keyword(s):

Model Theory ◽

Decision Procedures ◽

Logic Of Knowledge

We study monotonic and non-monotonic Logics of Knowledge, giving decision procedures and completeness results. In particular we develop a model theory for a non-monotonic Logic of Knowledge and show that it corresponds exactly to normal applications of a non-monotonic rule of inference due to McCarthy.

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Deciding Clause Classes by Semantic Clash Resolution

Fundamenta Informaticae ◽

10.3233/fi-1993-182-406 ◽

1993 ◽

Vol 18 (2-4) ◽

pp. 163-182

Author(s):

Alexander Leitsch

Keyword(s):

Decision Procedure ◽

Decision Procedures ◽

General Concept ◽

Complexity Measure ◽

Syntactical Structure

It is investigated, how semantic clash resolution can be used to decide some classes of clause sets. Because semantic clash resolution is complete, the termination of the resolution procedure on a class Γ gives a decision procedure for Γ. Besides generalizing earlier results we investigate the relation between termination and clause complexity. For this purpose we define the general concept of atom complexity measure and show some general results about termination in terms of such measures. Moreover, rather than using fixed resolution refinements we define an algorithmic generator for decision procedures, which constructs appropriate semantic refinements out of the syntactical structure of the clause sets. This method is applied to the Bernays – Schönfinkel class, where it gives an efficient (resolution) decision procedure.

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Are there similarities between the Corona and the climate crisis?

Journal of Environmental Studies and Sciences ◽

10.1007/s13412-021-00666-5 ◽

2021 ◽

Author(s):

Robert C. Schmidt

Keyword(s):

Climate Change ◽

Political Parties ◽

Decision Procedures ◽

Free Rider ◽

Decision Makers ◽

Short Paper ◽

Political Decision ◽

Look Back ◽

Policy Measures ◽

Climate Crisis

AbstractIn this short paper, I look back at the early stages of the Corona crisis, around early February 2020, and compare the situation with the climate crisis. Although these two problems unfold on a completely different timescale (weeks in the case of Corona, decades in the case of climate change), I find some rather striking similarities between these two problems, related with issues such as uncertainty, free-rider incentives, and disincentives of politicians to adequately address the respective issue with early, farsighted and possibly harsh policy measures. I then argue that for complex problems with certain characteristics, it may be necessary to establish novel political decision procedures that sidestep the normal, day-to-day political proceedings. These would be procedures that actively involve experts, and lower the involvement of political parties as far as possible to minimize the decision-makers’ disincentives.

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