7,626 research outputs found
Identification and Estimation of Discrete Games of Complete Information
We discuss the identification and estimation of discrete games of complete information. Following Bresnahan and Reiss (1990, 1991), a discrete game is a generalization of a standard discrete choice model where utility depends on the actions of other players. Using recent algorithms to compute all of the Nash equilibria to a game, we propose simulation-based estimators for static, discrete games. With appropriate exclusion restrictions about how covariates enter into payoffs and influence equilibrium selection, the model is identified with only weak parametric assumptions. Monte Carlo evidence demonstrates that the estimator can perform well in moderately-sized samples. As an application, we study the strategic decision of firms in spatially-separated markets to establish a presence on the Internet.
Identification and Estimation of Discrete Games of Complete Information
We discuss the identification and estimation of discrete games with complete information. Following Bresnahan and Reiss, a discrete game is defined to be a generalization of a standard discrete choice model in which utility depends on the actions of other players. Using recent algorithms that compute the complete set of the Nash equilibria, we propose simulation-based estimators for static, discrete games. With appropriate exclusion restrictions about how covariates enter into payoffs and influence equilibrium selection, the model is identified with only weak parametric assumptions. Monte Carlo evidence demonstrates that the estimator can perform well in moderately-sized samples. As an illustration, we study the strategic decisions of firms in spatially-separated markets in establishing a presence on the InternetEmpirical Industrial Organization, Simulation Based Estimation, Homotopies
Adaptive Lock-Free Data Structures in Haskell: A General Method for Concurrent Implementation Swapping
A key part of implementing high-level languages is providing built-in and
default data structures. Yet selecting good defaults is hard. A mutable data
structure's workload is not known in advance, and it may shift over its
lifetime - e.g., between read-heavy and write-heavy, or from heavy contention
by multiple threads to single-threaded or low-frequency use. One idea is to
switch implementations adaptively, but it is nontrivial to switch the
implementation of a concurrent data structure at runtime. Performing the
transition requires a concurrent snapshot of data structure contents, which
normally demands special engineering in the data structure's design. However,
in this paper we identify and formalize an relevant property of lock-free
algorithms. Namely, lock-freedom is sufficient to guarantee that freezing
memory locations in an arbitrary order will result in a valid snapshot. Several
functional languages have data structures that freeze and thaw, transitioning
between mutable and immutable, such as Haskell vectors and Clojure transients,
but these enable only single-threaded writers. We generalize this approach to
augment an arbitrary lock-free data structure with the ability to gradually
freeze and optionally transition to a new representation. This augmentation
doesn't require changing the algorithm or code for the data structure, only
replacing its datatype for mutable references with a freezable variant. In this
paper, we present an algorithm for lifting plain to adaptive data and prove
that the resulting hybrid data structure is itself lock-free, linearizable, and
simulates the original. We also perform an empirical case study in the context
of heating up and cooling down concurrent maps.Comment: To be published in ACM SIGPLAN Haskell Symposium 201
On the Forward-Backward Asymmetry of Leptonic Decays of at the Fermilab Tevatron
We report on a study of the measurement techniques used to determine the
leptonic forward-backward asymmetry of top anti-top quark pairs in Tevatron
experiments with a proton anti-proton initial state. Recently it was shown that
a fit of the differential asymmetry as a function of (where
is the charge of the lepton from the cascade decay of the top quarks
and is the final pseudorapidity of the lepton in the detector frame)
to a hyperbolic tangent function can be used to extrapolate to the full
leptonic asymmetry. We find this empirical method to well reproduce the results
from current experiments, and present arguments as to why this is the case. We
also introduce two more models, based on Gaussian functions, that better model
the distribution. With our better understanding, we find that
the asymmetry is mainly determined by the shift of the mean of the
distribution, the main contribution to the inclusive asymmetry
comes from the region around , and the extrapolation from
the detector-covered region to the inclusive asymmetry is stable via a
multiplicative scale factor, giving us confidence in the previously reported
experimental results.Comment: 26 pages, 12 figure
Identification and Estimation of a Discrete Game of Complete Information
We discuss the identification and estimation of discrete games of complete information. Following Bresnahan and Reiss (1990, 1991), a discrete game is a generalization of a standard discrete choice model where utility depends on the actions of other players. Using recent algorithms to compute all of the Nash equilibria to a game, we propose simulation-based estimators for static, discrete games. We demonstrate that the model is identified under weak functional form assumptions using exclusion restrictions and an identification at infinity approach. Monte Carlo evidence demonstrates that the estimator can perform well in moderately sized samples. As an application, we study entry decisions by construction contractors to bid on highway projects in California. We find that an equilibrium is more likely to be observed if it maximizes joint profits, has a higher Nash product, uses mixed strategies, and is not Pareto dominated by another equilibrium.National Science Foundation (U.S.) (Grant SES-0339328)National Science Foundation (U.S.) (Grant SES-0452143
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