\documentclass[11pt]{article} \setlength{\oddsidemargin}{0.0truein} \setlength{\evensidemargin}{0.0truein} \setlength{\textwidth}{6.5truein} \setlength{\topmargin}{0.0truein} \setlength{\textheight}{9.0truein} \setlength{\headsep}{0.0truein} \setlength{\headheight}{0.0truein} \setlength{\topskip}{10.0pt} \setlength{\parskip}{5mm} \usepackage{url} \usepackage{amsmath} \usepackage{amssymb} \pagestyle{empty} \begin{document} \begin{center} \textbf{\Large{\textsc{STANFORD UNIVERSITY}}}\\[5pt] \textbf{\Large{\textsc{DEPARTMENT OF STATISTICS}}}\\[5pt] \Large{\textsc{FOUNDATIONS OF STATISTICS SEMINAR}} \end{center} % In the following statements, replace "Time of talk", % "Weekday", and "Date of talk". An example is provided. % If you are not sure about this, just skip this part. \begin{center} 3:15 p.m., Wednesday, November 21, 2007\\ %% Example: 4:15 p.m., Tuesday, February 13, 2007\\ Building 380, Room 380-C\\ \end{center} % In the following statements, replace "Name of the speaker" with your % name, "Department Affiliation" with your department affiliation, and %"University Affiliation" with your university affiliation. \begin{center} \textsl{Terrence L. Fine} \\ School of Electrical \& Computer Engineering\\ Cornell University\\ Ithaca, NY 14850 \end{center} % In the following statements, replace "Title of the talk" % with your title of the talk. \begin{center} \subsection*{Chaotic Probability: The Set of Measures Model} \end{center} % In the following statements, replace "Abstract of the talk" % with your abstract. \noindent We are motivated by the success of a sets of measures approach to representing the state of belief of an individual, as expressed through upper and lower previsions/expectations, to ask whether such a model can also describe some objective frequentist data sources. I report on joint work with Pablo I. Fierens and Leandro C. Rego on a probability model for sequences in which the conditional probability $\nu_i$ of the $i$-th random variable $X_i$, conditional upon all preceding random variables $X^{i-1} = x^{i-1}$, is chosen erratically from a set of measures $\mathcal{M}= \{\nu\}$, all being defined on the same finite sample space $\mathcal{X}$. Our interest is in the case where the function $F(x^{i-1})$ selecting the marginal $\nu_i$ is not effectively computable and not asymptotically estimable from the observed data $x^i$. We can think of this setup as arising from a game between two agents, although we are more interested in the possibility that the physical world provides examples of such erratic or highly irregular processes. Our goal is to estimate $\mathcal{M}$ by $\hat{\mathcal{M}}$ based upon $x^n$, for large enough $n$. We show the existence of a family $\Psi= \{\varphi\}$ of causal place selection rules, chosen independently of $\mathcal{M}$, that produce subsequences of the given data whose time averages provide the desired information about the elements of $\mathcal{M}$. We have not been able to show the converse that $\mathcal{M}$ is all that can be estimated. \end{document}