13,029 research outputs found
Strategy complexity of lim sup and lim inf payoff objectives in countable MDPs
No full textWe study countably infinite Markov decision processes (MDPs) with real-valued tran-
sition rewards. A strategy is a function which decides how plays proceed within the
MDP. Every strategy induces a set of infinite runs in the MDP and each infinite run
induces the following sequences of payoffs:
1. Point payoff (the sequence of directly seen transition rewards),
2. Mean payoff (the sequence of the sums of all rewards so far, divided by the number
of steps), and
3. Total payoff (the sequence of the sums of all rewards so far).
For each payoff type, the threshold objective is to maximise the probability that the
lim sup/lim inf is non-negative. We are interested in the strategy complexity of the
above objectives, i.e. the amount of memory and/or randomisation that a strategy
needs access to in order to play well (optimally resp. ε-optimally). Our results seek
not only to decide whether an objective requires finite or infinite memory, but in the
case of infinite memory, what kind of infinite memory is necessary and sufficient. For
example, a step counter which acts as a clock, or a reward counter which sums up the
seen rewards may be sufficient.
We compare the lim sup/lim inf point payoff objectives to the Büchi/co-Büchi ob-
jectives which, given a set of states or transitions, seek to maximise the probability
that this set is visited infinitely/finitely often. Convergence effects are what differen-
tiate lim sup/lim inf point payoff objectives from Büchi/co-Büchi. For example, the
sequence −1/2, −1/3, −1/4 . . . does satisfy lim sup ≥ 0 and lim inf ≥ 0 despite all of
the rewards being negative. It is in dealing with these effects which we make our main
technical contributions. We establish a complete picture of the strategy complexity for
both the lim sup and lim inf point payoff objectives. In particular we show that opti-
mal lim sup requires either randomisation or access to a step counter and that lim inf
of point payoff requires a step counter (but not more) when the underlying MDP is
infinitely branching.
We also comprehensively pin down the strategy complexity for the lim inf total
and mean payoff objectives. This result requires a novel counterexample involving
unboundedly growing rewards as well as finely tuned transition probabilities which
force the player to use memory in order to mimic what occurred in past random events.
This allows us to show that both of these objectives require the use of both a step
counter as well as a reward counter.
We apply our results to solve two open problems from Sudderth [35] about the
strategy complexity of optimal strategies for the expected lim sup/lim inf point pay-
off. We achieve this by reducing each objective to its respective optimal threshold
lim sup/lim inf point payoff counterpart. Thus we are able to conclude that they share
the same optimal strategy complexity
ROSENTHAL, Eric Inventory of documents
No full textCOVERAGE 1904; 1 File; 011 metre.Private papers of Eric Rosenthal, author, journalist and broadcaster
tritrophic-dispersal-model: Code used for creating figures for "Non-hierarchical dispersal promotes stability and resilience in a tri-trophic metacommunity"
No full text<p>This is the commented code used for creating figures for the paper. Any questions regarding the code should be directed to the corresponding author and repository owner (Eric Pedersen). </p>
Eric Velazquez Spanish Language Picture Book Award 2022 Acceptance Speech
No full textAuthor Eric Velazquez gives his Silver Medal acceptance speech for Pulpo Guisado (Holiday House)https://educate.bankstreet.edu/spanishlanguageaward/1001/thumbnail.jp
Eric C. Lincoln, Professor of Sociology and Religion, 1971
No full textThis is an interview with Eric C. Lincoln. Eric was a Professor of Sociology and religion, Union Theological Seminary and author of many books and articles on Negro history. In this recording the contributors discuss local memphis politics, sociology, and race relations compared to that of other cities in the South and the rest of the country
Interview with Eric Bentley, author, drama critic, and playwright
No full textDistinguished drama critic and Bertolt Brecht scholar, Eric Bentley is interviewed by WTMJ-TV host Jim Peck and John B. Fuegi, associate professor of Comparative Literature. Bentley recalls his association with Brecht, the critical and creative aspects of literature, and his interest in writing plays for the theater.GrayscaleSoun
Dr. Eric Yellin – Faculty Author Interview
No full textDr. Eric Yellin, Associate Professor of History and American Studies discusses his new book, Racism in the Nation’s Service: Government Workers and the Color Line in Woodrow Wilson’s America, published recently by the University of North Carolina Press. In this book, Dr. Yellin argues that President Wilson’s administration successfully segregated the federal government in the age of progressive politics. He investigates how the enactment of the segregation policy imposed a color line on American opportunity and implicated Washington in the economic limitation of African Americans for decades to com
Essentials of Dental Radiography and Radiology / Eric Whaites and Nicholas Drage.
No full textPrevious edition: Essentials of dental radiography and radiology / Eric Whaites. Fourth edition. Edinburgh ; New York : Churchill Livingstone, 2007.Includes bibliographical references (pages 461-464) and index.x, 478, [2] pages
10th C. Eric Lincoln Lecture Series, 1992
No full textPart of the 10th anniversary of the C. Eric Lincoln lecture series Dr. Love Henry Whelchel moderates a panel of scholars. The panel includes Dr. C. Eric Lincoln, Dr. Jacquelyn Grant, and Dr. John Hope Franklin. The panel discusses the life of George Washington Williams (author of History of the Negro Race in America). The discussion includes issues related to Womanist theology, Islamic religion, sociology, religion and history.The Atlanta University Center Robert W. Woodruff Library acknowledges the generous support of the National Endowment for Humanities - Humanities Collections and Reference Resources Implementation Project Grant in supporting the processing and digitization of a number of its major archival collections as part of the project: Spreading the Word: Expanding Access to African American Religious Archival Collections at the Atlanta University Center Robert W. Woodruff Library
Q & A - Eric Davidson
No full textEric Davidson graduated from the University of Pennsylvania in 1954 and received his PhD from Rockefeller University in 1963. He remained at Rockefeller until 1971 when he moved to Caltech in Pasadena, California. He was elected to the U.S. National Academy of Sciences in 1985, and is at present Norman Chandler Professor of Cell Biology in the Division of Biology, Caltech. He is the author of 5 books and over 400 papers on developmental gene regulation and evolution of genomic programs for development. For the last decade his work has focused on theory and operation of developmental gene regulatory networks
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