The sweet mystery of compatibilism

Any satisfactory account of freedom must capture, or at least permit, the mysteriousness of freedom—a “sweet” mystery involving a certain kind of ignorance rather than a “sour” mystery of unintelligibility, incoherence, or unjustifiedness. I argue that compatibilism can capture the sweet mystery of freedom. I argue first that an action is free if and only if a certain “rationality constraint” is satisfied, and that nothing in standard libertarian accounts of freedom entails its satisfaction. Satisfaction of this constraint is consistent with the universal causal predetermination of action (UCP). If UCP is true and the rationality constraint satisfied, there’s a sense in which our actions are explanatorily (though not necessarily causally) overdetermined. While it seems plausible (given UCP) that our actions are so overdetermined, it seems utterly mysterious why they should be so overdetermined. Compatibilism’s capacity to accommodate this mystery is a mark in its favor.     

A bootstrap-based aggregate classifier for model-based clustering

In model-based clustering, a situation in which true class labels are unknown and that is therefore also referred to as unsupervised learning, observations are typically classified by the Bayes modal rule. In this study, we assess whether alternative classifiers from the classification or supervised-learning literature—developed for situations in which class labels are known—can improve the Bayes rule. More specifically, we investigate the performance of bootstrap-based aggregate (bagging) rules after adapting these to the model-based clustering context. It is argued that specific issues, such as the label-switching problem, have to be carefully addressed when using bootstrap methods in model-based clustering. Our two Monte Carlo studies show that classification based on the Bayes rule is rather stable and difficult to improve by bootstrap-based aggregate rules, even for sparse data. An empirical example illustrates the various approaches described in this paper.     

Generalized coherent states for oscillators connected with Meixner and Meixner—Pollaczek polynomials

The authors continue to study generalized coherent states for oscillator-like systems connected with a given family of orthogonal polynomials. In this work, we consider oscillators connected with Meixner and Meixner— Pollaczek polynomials and define generalized coherent states for these oscillators. A completeness condition for these states is proved by solution of a related classical moment problem. The results are compared with the other authors ones. In particular, we show that the Hamiltonian of the relativistic model of a linear harmonic oscillator can be treated as the linearization of a quadratic Hamiltonian, which arises naturally in our formalism. Bibliography: 56 titles. The authors dedicate this work to their friend and colleague P. P. Kulish on the occasion of his 60th birthday __________ Translated from Zapiski Nauchnykh Seminarov POMI, Vol. 317, 2004, pp. 66–93.     

Expressing One’s Mind

Remarks such as ‘I am in pain’ and ‘I think that it’s raining’ are puzzling, since they seem to literally describe oneself as being in pain or having a particular thought, but their conditions of use tend to coincide with unequivocal expressions of pain or of that thought. This led Wittgenstein, among others, to treat such remarks as expressing, rather than as reporting, one’s mental states. Though such expressivism is widely recognized as untenable, Bar-On has recently advanced a neo-expressivist view, on which such remarks exhibit characteristics of both expressions of mental states and reports of those states. I argue against any attempt to see such remarks as both reporting and expressing the same mental states, and that a correct account rests on distinguishing the truth conditions of such remarks from their conditions of use.     

A link between sequential semi-anonymous nonatomic games and their large finite counterparts

We show that obtainable equilibria of a multi-period nonatomic game can be used by players in its large finite counterparts to achieve near-equilibrium payoffs. Such equilibria in the form of random state-to-action rules are parsimonious in form and easy to execute, as they are both oblivious of past history and blind to other players’ present states. Our transient results can be extended to a stationary case, where the finite multi-period games are special discounted stochastic games. In both nonatomic and finite games, players’ states influence their payoffs along with actions they take; also, the random evolution of one particular player’s state is driven by all players’ states as well as actions. The finite games can model diverse situations such as dynamic price competition. But they are notoriously difficult to analyze. Our results thus suggest ways to tackle these problems approximately.     

Meta-ethics and Justification

The author takes up three metaphysical conceptions of morality — realism, projectivism, constructivism — and the account of justification or reason that makes these pictures possible. It is argued that the right meta-ethical conception should be the one that entails the most plausible conception of reason-giving, rather than by any other consideration. Realism and projectivism, when understood in ways consistent with their fundamental commitments, generate unsatisfactory models of justification; constructivism alone does not. The author also argues for a particular interpretation of how “objective moral obligation” is to be understood within constructivism.

On evolution of an information dynamic system and its generating operator

States of a dynamical information system can be represented by points on a statistical manifold—a subset of a vector space endowed with an information topology. An evolution of such a system is considered here with respect to changes in information rather than changes in time, because differences between states are represented by an information distance. Here we consider an optimal system maximizing a utility of an abstract information resource, and then analyze properties of information such that an optimal system is described by an evolution operator or a semigroup. The latter is generated by an operator that can be interpreted as a utility, payoff or a fitness function. We discuss the advantages and applications of the proposed approach.     

Function Spaces and Capacity Related to a Sublinear Expectation: Application to <Emphasis Type="Italic">G</Emphasis>-Brownian Motion Paths

In this paper we give some basic and important properties of several typical Banach spaces of functions of G-Brownian motion paths induced by a sublinear expectation—G-expectation. Many results can be also applied to more general situations. A generalized version of Kolmogorov’s criterion for continuous modification of a stochastic process is also obtained. The results can be applied in continuous time dynamic and coherent risk measures in finance, in particular for path-dependence risky positions under situations of volatility model uncertainty.     

Cartesians,Strawsonians and the univocal meaning of mental predicates

The paper examines the Cartesian and the Strawsonian answers to the question of why self-applied and other-applied mental predicates mean the same. While these answers relate to different, complementary aspects of this question, they seem and are usually considered as incompatible. Indeed, their apparent incompatibility constitutes a major objection to the Cartesian answer. A primary aim of the paper is to show that the Strawsonian answer does not pose a real problem to the Cartesian answer. Unlike other attempts to show this, the paper does not seek to undermine the Strawsonian answer. Indeed, its second aim is to defend this answer against these other attempts. The paper’s strategy in defending the Cartesian answer is to show that the framework underlying this answer can — indeed, for internal reasons, must — accommodate the Strawsonian answer. By showing this, the paper also shows that a Cartesian framework can provide a comprehensive answer to the aforementioned question, which is its third aim.     

Maslov probability spaces related to the Bose—Einstein and Fermi—Dirac statistics

For systems of indistinguishable particles, we describe probability spaces factored by the equivalence relations identifying configurations which differ by permutation of particles, under the condition that identical states are forbidden (Fermi—Dirac statistics) or admissible (Bose—Einstein statistics). It is assumed that the states of particles have different probabilities; these correspond either to the presence of an external potential, or to a pair interaction potential, or to a collective interaction. The spaces constructed in the paper are related to specific queuing models. Translated fromMatematicheskie Zametki, Vol. 65, No. 5, pp. 746–759, May, 1999.     

The graphs of polytopes with involutory automorphisms

Steinitz’ theorem states that a graph is the graph of a 3-dimensional convex polytope if and only if it is planar and 3-connected. Grünbaum has shown that Steinitz’ proof can be modified to characterize the graphs of polytopes that are centrally symmetric or have a plane of symmetry. We show how to modify Steinitz’ proof to take care of the remaining involutory case—polytopes that are symmetric about a line. Research supported by NSF Grant GP-3470.     

Quasi-stationary Distributions for a Class of Discrete-time Markov Chains

This paper is concerned with the circumstances under which a discrete-time absorbing Markov chain has a quasi-stationary distribution. We showed in a previous paper that a pure birth-death process with an absorbing bottom state has a quasi-stationary distribution—actually an infinite family of quasi-stationary distributions— if and only if absorption is certain and the chain is geometrically transient. If we widen the setting by allowing absorption in one step (killing) from any state, the two conditions are still necessary, but no longer sufficient. We show that the birth–death-type of behaviour prevails as long as the number of states in which killing can occur is finite. But if there are infinitely many such states, and if the chain is geometrically transient and absorption certain, then there may be 0, 1, or infinitely many quasi-stationary distributions. Examples of each type of behaviour are presented. We also survey and supplement the theory of quasi-stationary distributions for discrete-time Markov chains in general.      

Comparison and robustification of Bayes and Black-Litterman models

For determining an optimal portfolio allocation, parameters representing the underlying market—characterized by expected asset returns and the covariance matrix—are needed. Traditionally, these point estimates for the parameters are obtained from historical data samples, but as experts often have strong opinions about (some of) these values, approaches to combine sample information and experts’ views are sought for. The focus of this paper is on the two most popular of these frameworks—the Black-Litterman model and the Bayes approach. We will prove that—from the point of traditional portfolio optimization—the Black-Litterman is just a special case of the Bayes approach. In contrast to this, we will show that the extensions of both models to the robust portfolio framework yield two rather different robustified optimization problems.     

Efficiency in the trust game: an experimental study of precommitment

We experimentally test a precommitment mechanism for the trust game. Before the investor’s decision, the allocator places an amount into escrow, to be forfeited if he keeps the proceeds of investment for himself. We vary the available escrow amounts—in particular, whether there is a high amount that gives rise to an efficient equilibrium—and whether escrow is voluntary or imposed. We find that when chosen, the high escrow amount does lead to efficient outcomes. We also find substantial investment when the high amount is unavailable or not chosen, though well below that when it is chosen, and declining over time. We find only weak evidence for behavioral theories, such as crowding out and signaling. These results are seen when escrow choices are imposed as well as when they are voluntary.      

Markov-modulated Hawkes process with stepwise decay

This paper proposes a new model—the Markov-modulated Hawkes process with stepwise decay (MMHPSD)—to investigate the variation in seismicity rate during a series of earthquake sequences including multiple main shocks. The MMHPSD is a self-exciting process which switches among different states, in each of which the process has distinguishable background seismicity and decay rates. Parameter estimation is developed via the expectation maximization algorithm. The model is applied to data from the Landers–Hector Mine earthquake sequence, demonstrating that it is useful for modelling changes in the temporal patterns of seismicity. The states in the model can capture the behavior of main shocks, large aftershocks, secondary aftershocks, and a period of quiescence with different background rates and decay rates.     

Collars and partitions of hyperbolic cone-surfaces

For compact Riemann surfaces, the collar theorem and Bers’ partition theorem are major tools for working with simple closed geodesics. The main goal of this article is to prove similar theorems for hyperbolic cone-surfaces. Hyperbolic two-dimensional orbifolds are a particular case of such surfaces. We consider all cone angles to be strictly less than π to be able to consider partitions. Emily B. Dryden—partially supported by the US National Science Foundation grant DMS-0306752. Hugo Parlier—supported by the Swiss National Science Foundation grants 21-57251.99 and 20-68181.02.     

Covariant and dynamical reduction for principal bundle field theories

Reduction for field theories with symmetry can be done either covariantly—that is, on spacetime—or dynamically—that is, after spacetime is split into space and time. The purpose of this article is to show that these two reduction procedures are, in an appropriate sense, equivalent for a class of field theories whose fields take values in a principal bundle. One can think of this class of field theories as including examples such as a “sea of rigid bodies” with and appropriate interbody coupling potential.     

Constructing Knowledge Via a Peer Interaction in a CAS Environment with Tasks Designed from a Task–Technique–Theory Perspective

Our research project aimed at understanding the complexity of the construction of knowledge in a CAS environment. Basing our work on the French instrumental approach, in particular the Task–Technique–Theory (T–T–T) theoretical frame as adapted from Chevallard’s Anthropological Theory of Didactics, we were mindful that a careful task design process was needed in order to promote in students rich and meaningful learning. In this paper, we explore further Lagrange’s (2000) conjecture that the learning of techniques can foster conceptual understanding by investigating at close range the task-based activity of a pair of 10th grade students—activity that illustrates the ways in which the use of symbolic calculators along with appropriate tasks can stimulate the emergence of epistemic actions within technique-oriented algebraic activity.     

Viscosity Solutions of an Infinite-Dimensional Black—Scholes—Barenblatt Equation

We study an infinite-dimensional Black—Scholes—Barenblatt equation which is a Hamilton—Jacobi—Bellman equation that is related to option pricing in the Musiela model of interest rate dynamics. We prove the existence and uniqueness of viscosity solutions of the Black—Scholes—Barenblatt equation and discuss their stochastic optimal control interpretation. We also show that in some cases the solution can be locally uniformly approximated by solutions of suitable finite-dimensional Hamilton—Jacobi—Bellman equations.