Anonymity in predicting the future

Amherst College Digital Collections > The Octagon

Creator	Velleman, Daniel J.
Creator	Bajpai, Dvij
Title	Anonymity in predicting the future
Abstract	Consider an arbitrary set S and an arbitrary function f : ℝ → S. We think of the domain of f as representing time, and for each x ∈ ℝ, we think of f(x) as the state of some system at time x. Imagine that, at each time x, there is an agent who can see the values of f on (−∞, x) and is trying to guess f(x)—in other words, the agent is trying to guess the present state of the system from its past history. In a 2008 paper, Christopher Hardin and Alan Taylor use the axiom of choice to construct a strategy that the agents can use to guarantee that, for every function f, all but countably many of them will guess correctly. In a 2013 monograph, they introduce the idea of anonymous guessing strategies, in which the agents can see the past but don't know where they are located in time. In this paper, we consider a number of variations on anonymity. For instance, what if, in addition to not knowing where they are located in time, agents also do not know the rate at which time is progressing? What if they have no sense of how much time elapses between any two events? We show that in some cases agents can still guess successfully, while in others they perform very poorly.
Notes	Copyright 2016 Mathematical Association of America. All Rights Reserved.
Publication Date	October 1, 2016
Identifier (DOI)	10.4169/amer.math.monthly.123.08.777
Citation	Bajpai, Dvij, and Daniel J. Velleman. Anonymity in Predicting the Future." American Mathematical Monthly 123. October (2016): 777-788.
Languages	English
Edition	Published Version
Genre	Articles
Subject	Mathematics
Subject	Axiom of choice
Part of	The Amherst College Octagon
Repository	The Amherst College Octagon
Rights	Creative Commons Attribution-NonCommercial-NoDerivatives license (CC BY NC ND 4.0)