10,673 research outputs found
Recursive Inspection Games
We consider a sequential inspection game where an inspector uses a limited
number of inspections over a larger number of time periods to detect a
violation (an illegal act) of an inspectee. Compared with earlier models, we
allow varying rewards to the inspectee for successful violations. As one
possible example, the most valuable reward may be the completion of a sequence
of thefts of nuclear material needed to build a nuclear bomb. The inspectee can
observe the inspector, but the inspector can only determine if a violation
happens during a stage where he inspects, which terminates the game; otherwise
the game continues. Under reasonable assumptions for the payoffs, the
inspector's strategy is independent of the number of successful violations.
This allows to apply a recursive description of the game, even though this
normally assumes fully informed players after each stage. The resulting
recursive equation in three variables for the equilibrium payoff of the game,
which generalizes several other known equations of this kind, is solved
explicitly in terms of sums of binomial coefficients. We also extend this
approach to non-zero-sum games and, similar to Maschler (1966), "inspector
leadership" where the inspector commits to (the same) randomized inspection
schedule, but the inspectee acts legally (rather than mixes as in the
simultaneous game) as long as inspections remain.Comment: final version for Mathematics of Operations Research, new Theorem
Inspection and crime prevention : an evolutionary perspective
In this paper, we analyse inspection games with an evolutionary perspective. In our evolutionary inspection game with a large population, each individual is not a rational payoff maximiser, but periodically updates his strategy if he perceives that other individuals' strategies are more successful than his own, namely strategies are subject to the evolutionary pressure. We develop this game into a few directions. Firstly, social norms are incorporated into the game and we analyse how social norms may influence individuals' propensity to engage in criminal behaviour. Secondly, a forward-looking inspector is considered, namely, the inspector chooses the level of law enforcement whilst taking into account the effect that this choice will have on future crime rates. Finally, the game is extended to the one with continuous strategy spaces
Computability of simple games: A complete investigation of the sixty-four possibilities
Classify simple games into sixteen "types" in terms of the four conventional
axioms: monotonicity, properness, strongness, and nonweakness. Further classify
them into sixty-four classes in terms of finiteness (existence of a finite
carrier) and algorithmic computability. For each such class, we either show
that it is empty or give an example of a game belonging to it. We observe that
if a type contains an infinite game, then it contains both computable ones and
noncomputable ones. This strongly suggests that computability is logically, as
well as conceptually, unrelated to the conventional axioms.Comment: 25 page
Soft Contract Verification
Behavioral software contracts are a widely used mechanism for governing the
flow of values between components. However, run-time monitoring and enforcement
of contracts imposes significant overhead and delays discovery of faulty
components to run-time.
To overcome these issues, we present soft contract verification, which aims
to statically prove either complete or partial contract correctness of
components, written in an untyped, higher-order language with first-class
contracts. Our approach uses higher-order symbolic execution, leveraging
contracts as a source of symbolic values including unknown behavioral values,
and employs an updatable heap of contract invariants to reason about
flow-sensitive facts. We prove the symbolic execution soundly approximates the
dynamic semantics and that verified programs can't be blamed.
The approach is able to analyze first-class contracts, recursive data
structures, unknown functions, and control-flow-sensitive refinements of
values, which are all idiomatic in dynamic languages. It makes effective use of
an off-the-shelf solver to decide problems without heavy encodings. The
approach is competitive with a wide range of existing tools---including type
systems, flow analyzers, and model checkers---on their own benchmarks.Comment: ICFP '14, September 1-6, 2014, Gothenburg, Swede
Generating and Solving Symbolic Parity Games
We present a new tool for verification of modal mu-calculus formulae for
process specifications, based on symbolic parity games. It enhances an existing
method, that first encodes the problem to a Parameterised Boolean Equation
System (PBES) and then instantiates the PBES to a parity game. We improved the
translation from specification to PBES to preserve the structure of the
specification in the PBES, we extended LTSmin to instantiate PBESs to symbolic
parity games, and implemented the recursive parity game solving algorithm by
Zielonka for symbolic parity games. We use Multi-valued Decision Diagrams
(MDDs) to represent sets and relations, thus enabling the tools to deal with
very large systems. The transition relation is partitioned based on the
structure of the specification, which allows for efficient manipulation of the
MDDs. We performed two case studies on modular specifications, that demonstrate
that the new method has better time and memory performance than existing PBES
based tools and can be faster (but slightly less memory efficient) than the
symbolic model checker NuSMV.Comment: In Proceedings GRAPHITE 2014, arXiv:1407.767
A recursive core for partition function form games
We present a new solution to partition function form games that is novel in at least two ways. Firstly, the solution exploits the consistency of the partition function form, namely that the response to a deviation is established as the same solution applied to the residual game, itself a partition function form game. This consistency allows us to model residual behaviour in a natural, intuitive way. Secondly, we consider a pair of solutions as the extrema of an interval for set inclusion. Taking the whole interval rather than just one of the extremes enables us to include or exclude outcomes with certainty.microeconomics ;
The Core of a Partition Function Game
We consider partition function games and introduce new defini-tions of the core that include the effects of externalities. We assume that all players behave rationally and that all stable outcomes arising are consistent with the appropriate generalised concept of the core. The result is a recursive definition of the core where residual subgames are considered as games with fewer players and with a partition function that captures the externalities of the deviating coalition. Some properties of the new concepts are discussed.core, partition function, externalities
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