How Long To Equilibrium? The Communication Complexity Of Uncoupled Equilibrium Procedures
In: Simple Adaptive Strategies From Regret-Matching to Uncoupled Dynamics
Author
Abstract
Suggested Citation
Download full text from publisher
As the access to this document is restricted, you may want to look for a different version below or search for a different version of it.
Other versions of this item:
- Hart, Sergiu & Mansour, Yishay, 2010. "How long to equilibrium? The communication complexity of uncoupled equilibrium procedures," Games and Economic Behavior, Elsevier, vol. 69(1), pages 107-126, May.
References listed on IDEAS
- Fudenberg, Drew & Levine, David, 1998.
"Learning in games,"
European Economic Review, Elsevier, vol. 42(3-5), pages 631-639, May.
- Drew Fudenberg & David K. Levine, 1998. "Learning in Games," Levine's Working Paper Archive 2222, David K. Levine.
- Germano, Fabrizio & Lugosi, Gabor, 2007.
"Global Nash convergence of Foster and Young's regret testing,"
Games and Economic Behavior, Elsevier, vol. 60(1), pages 135-154, July.
- Fabrizio Germano & Gábor Lugosi, 2004. "Global Nash convergence of Foster and Young's regret testing," Economics Working Papers 788, Department of Economics and Business, Universitat Pompeu Fabra.
- Jordan J. S., 1993. "Three Problems in Learning Mixed-Strategy Nash Equilibria," Games and Economic Behavior, Elsevier, vol. 5(3), pages 368-386, July.
- Sergiu Hart, 2013.
"Adaptive Heuristics,"
World Scientific Book Chapters, in: Simple Adaptive Strategies From Regret-Matching to Uncoupled Dynamics, chapter 11, pages 253-287,
World Scientific Publishing Co. Pte. Ltd..
- Sergiu Hart, 2005. "Adaptive Heuristics," Econometrica, Econometric Society, vol. 73(5), pages 1401-1430, September.
- Sergiu Hart, 2004. "Adaptive Heuristics," Discussion Paper Series dp372, The Federmann Center for the Study of Rationality, the Hebrew University, Jerusalem.
- Sergiu Hart, 2004. "Adaptive Heuristics," Levine's Bibliography 122247000000000471, UCLA Department of Economics.
- Kalai, Ehud & Lehrer, Ehud, 1993.
"Rational Learning Leads to Nash Equilibrium,"
Econometrica, Econometric Society, vol. 61(5), pages 1019-1045, September.
- Ehud Kalai & Ehud Lehrer, 1990. "Rational Learning Leads to Nash Equilibrium," Discussion Papers 895, Northwestern University, Center for Mathematical Studies in Economics and Management Science.
- Kalai, Ehud & Lehrer, Ehud, 1991. "Rational Learning Leads to Nash Equilibrium," Working Papers 91-18, C.V. Starr Center for Applied Economics, New York University.
- E. Kalai & E. Lehrer, 2010. "Rational Learning Leads to Nash Equilibrium," Levine's Working Paper Archive 529, David K. Levine.
- Ehud Kalai & Ehud Lehrer, 1990. "Rational Learning Leads to Nash Equilibrium," Discussion Papers 925, Northwestern University, Center for Mathematical Studies in Economics and Management Science.
- Foster, Dean P. & Vohra, Rakesh V., 1997. "Calibrated Learning and Correlated Equilibrium," Games and Economic Behavior, Elsevier, vol. 21(1-2), pages 40-55, October.
- Sergiu Hart & Andreu Mas-Colell, 2013.
"A General Class Of Adaptive Strategies,"
World Scientific Book Chapters, in: Simple Adaptive Strategies From Regret-Matching to Uncoupled Dynamics, chapter 3, pages 47-76,
World Scientific Publishing Co. Pte. Ltd..
- Hart, Sergiu & Mas-Colell, Andreu, 2001. "A General Class of Adaptive Strategies," Journal of Economic Theory, Elsevier, vol. 98(1), pages 26-54, May.
- Sergiu Hart & Andreu Mas-Colell, 1999. "A General Class of Adaptive Strategies," Game Theory and Information 9904001, University Library of Munich, Germany, revised 23 Mar 2000.
- Sergiu Hart & Andreu Mas-Colell, 1999. "A general class of adaptative strategies," Economics Working Papers 373, Department of Economics and Business, Universitat Pompeu Fabra.
- Jordan, J. S., 1991.
"Bayesian learning in normal form games,"
Games and Economic Behavior, Elsevier, vol. 3(1), pages 60-81, February.
- Jordan, J.S., 1990. "Bayesian Learning in Normal Form Games," Papers 257, Minnesota - Center for Economic Research.
- J. Jordan, 2010. "Bayesian Learning in Normal Form Games," Levine's Working Paper Archive 573, David K. Levine.
- Sergiu Hart & Andreu Mas-Colell, 2013.
"Stochastic Uncoupled Dynamics And Nash Equilibrium,"
World Scientific Book Chapters, in: Simple Adaptive Strategies From Regret-Matching to Uncoupled Dynamics, chapter 8, pages 165-189,
World Scientific Publishing Co. Pte. Ltd..
- Hart, Sergiu & Mas-Colell, Andreu, 2006. "Stochastic uncoupled dynamics and Nash equilibrium," Games and Economic Behavior, Elsevier, vol. 57(2), pages 286-303, November.
- Sergiu Hart & Andreu Mas-Colell, 2004. "Stochastic Uncoupled Dynamics and Nash Equilibrium," Levine's Bibliography 122247000000000466, UCLA Department of Economics.
- Sergiu Hart & Andreu Mas-Colell, 2004. "Stochastic Uncoupled Dynamics and Nash Equilibrium," Discussion Paper Series dp371, The Federmann Center for the Study of Rationality, the Hebrew University, Jerusalem.
- Sergiu Hart & Andreu Mas-Colell, 2004. "Stochastic Uncoupled Dynamics and Nash Equilibrium," Working Papers 174, Barcelona School of Economics.
- Sergiu Hart & Andreu Mas-Colell, 2004. "Stochastic uncoupled dynamics and Nash equilibrium," Economics Working Papers 783, Department of Economics and Business, Universitat Pompeu Fabra.
- Foster, Dean P. & Young, H. Peyton, 2003.
"Learning, hypothesis testing, and Nash equilibrium,"
Games and Economic Behavior, Elsevier, vol. 45(1), pages 73-96, October.
- Peyton Young, 2002. "Learning Hypothesis Testing and Nash Equilibrium," Economics Working Paper Archive 474, The Johns Hopkins University,Department of Economics.
- Sergiu Hart & Andreu Mas-Colell, 2013.
"A Simple Adaptive Procedure Leading To Correlated Equilibrium,"
World Scientific Book Chapters, in: Simple Adaptive Strategies From Regret-Matching to Uncoupled Dynamics, chapter 2, pages 17-46,
World Scientific Publishing Co. Pte. Ltd..
- Sergiu Hart & Andreu Mas-Colell, 2000. "A Simple Adaptive Procedure Leading to Correlated Equilibrium," Econometrica, Econometric Society, vol. 68(5), pages 1127-1150, September.
- Sergiu Hart & Andreu Mas-Colell, 1996. "A simple adaptive procedure leading to correlated equilibrium," Economics Working Papers 200, Department of Economics and Business, Universitat Pompeu Fabra, revised Dec 1996.
- Sergiu Hart & Andreu Mas-Colell, 1997. "A Simple Adaptive Procedure Leading to Correlated Equilibrium," Game Theory and Information 9703006, University Library of Munich, Germany, revised 25 Nov 1997.
- S. Hart & A. Mas-Collel, 2010. "A Simple Adaptive Procedure Leading to Correlated Equilibrium," Levine's Working Paper Archive 572, David K. Levine.
- Amotz Cahn, 2004. "General procedures leading to correlated equilibria," International Journal of Game Theory, Springer;Game Theory Society, vol. 33(1), pages 21-40, January.
- Aumann, Robert J., 1974.
"Subjectivity and correlation in randomized strategies,"
Journal of Mathematical Economics, Elsevier, vol. 1(1), pages 67-96, March.
- AUMANN, Robert J., 1974. "Subjectivity and correlation in randomized strategies," LIDAM Reprints CORE 167, Université catholique de Louvain, Center for Operations Research and Econometrics (CORE).
- R. Aumann, 2010. "Subjectivity and Correlation in Randomized Strategies," Levine's Working Paper Archive 389, David K. Levine.
- Young, H. Peyton, 2004. "Strategic Learning and its Limits," OUP Catalogue, Oxford University Press, number 9780199269181.
- Sergiu Hart & Andreu Mas-Colell, 2013.
"Uncoupled Dynamics Do Not Lead To Nash Equilibrium,"
World Scientific Book Chapters, in: Simple Adaptive Strategies From Regret-Matching to Uncoupled Dynamics, chapter 7, pages 153-163,
World Scientific Publishing Co. Pte. Ltd..
- Sergiu Hart & Andreu Mas-Colell, 2003. "Uncoupled Dynamics Do Not Lead to Nash Equilibrium," American Economic Review, American Economic Association, vol. 93(5), pages 1830-1836, December.
- , P. & , Peyton, 2006. "Regret testing: learning to play Nash equilibrium without knowing you have an opponent," Theoretical Economics, Econometric Society, vol. 1(3), pages 341-367, September.
- Sergiu Hart & David Schmeidler, 2013.
"Existence Of Correlated Equilibria,"
World Scientific Book Chapters, in: Simple Adaptive Strategies From Regret-Matching to Uncoupled Dynamics, chapter 1, pages 3-14,
World Scientific Publishing Co. Pte. Ltd..
- Sergiu Hart & David Schmeidler, 1989. "Existence of Correlated Equilibria," Mathematics of Operations Research, INFORMS, vol. 14(1), pages 18-25, February.
- Drew Fudenberg & David K. Levine, 1998.
"The Theory of Learning in Games,"
MIT Press Books,
The MIT Press,
edition 1, volume 1, number 0262061945, April.
- Drew Fudenberg & David K. Levine, 1996. "The Theory of Learning in Games," Levine's Working Paper Archive 624, David K. Levine.
- Stoltz, Gilles & Lugosi, Gabor, 2007. "Learning correlated equilibria in games with compact sets of strategies," Games and Economic Behavior, Elsevier, vol. 59(1), pages 187-208, April.
- Monderer, Dov & Shapley, Lloyd S., 1996. "Potential Games," Games and Economic Behavior, Elsevier, vol. 14(1), pages 124-143, May.
Citations
Citations are extracted by the CitEc Project, subscribe to its RSS feed for this item.
Cited by:
- Hart, Sergiu & Nisan, Noam, 2018.
"The query complexity of correlated equilibria,"
Games and Economic Behavior, Elsevier, vol. 108(C), pages 401-410.
- Sergiu Hart & Noam Nisan, 2013. "The Query Complexity of Correlated Equilibria," Discussion Paper Series dp647, The Federmann Center for the Study of Rationality, the Hebrew University, Jerusalem.
- Sergiu Hart & Noam Nisan, 2013. "The Query Complexity of Correlated Equilibria," Levine's Working Paper Archive 786969000000000819, David K. Levine.
- Sergiu Hart & Noam Nisan, 2013. "The Query Complexity of Correlated Equilibria," Papers 1305.4874, arXiv.org, revised Dec 2017.
- Tom Johnston & Michael Savery & Alex Scott & Bassel Tarbush, 2023. "Game Connectivity and Adaptive Dynamics," Papers 2309.10609, arXiv.org, revised Oct 2024.
- Babichenko, Yakov & Rubinstein, Aviad, 2022. "Communication complexity of approximate Nash equilibria," Games and Economic Behavior, Elsevier, vol. 134(C), pages 376-398.
- Pradelski, Bary S.R. & Young, H. Peyton, 2012.
"Learning efficient Nash equilibria in distributed systems,"
Games and Economic Behavior, Elsevier, vol. 75(2), pages 882-897.
- H Peyton Young & Bary S. R. Pradelski, 2010. "Learning Efficient Nash Equilibria in Distributed Systems," Economics Series Working Papers 480, University of Oxford, Department of Economics.
- Goldberg, Paul W. & Pastink, Arnoud, 2014. "On the communication complexity of approximate Nash equilibria," Games and Economic Behavior, Elsevier, vol. 85(C), pages 19-31.
- Jiang, Albert Xin & Leyton-Brown, Kevin, 2015. "Polynomial-time computation of exact correlated equilibrium in compact games," Games and Economic Behavior, Elsevier, vol. 91(C), pages 347-359.
- Fabrizio Germano & Peio Zuazo-Garin, 2017.
"Bounded rationality and correlated equilibria,"
International Journal of Game Theory, Springer;Game Theory Society, vol. 46(3), pages 595-629, August.
- Fabrizio Germano & Peio Zuazo-Garin, 2015. "Bounded Rationality and Correlated Equilibria," AMSE Working Papers 1551, Aix-Marseille School of Economics, France, revised 02 Nov 2015.
- Germano, Fabrizio & Zuazo-Garin, Peio, 2015. "Bounded Rationality and Correlated Equilibria," Working Papers 2072/260959, Universitat Rovira i Virgili, Department of Economics.
- Fabrizio Germano & Peio Zuazo-Garin, 2015. "Bounded Rationality and Correlated Equilibria," Working Papers 812, Barcelona School of Economics.
- Fabrizio Germano & Peio Zuazo-Garin, 2015. "Bounded Rationality and Correlated Equilibria," Working Papers halshs-01251512, HAL.
- Fabrizio Germano & Peio Zuazo-Garin, 2015. "Bounded rationality and correlated equilibria," Economics Working Papers 1468, Department of Economics and Business, Universitat Pompeu Fabra.
- Cheung, Yun Kuen & Cole, Richard & Devanur, Nikhil R., 2020. "Tatonnement beyond gross substitutes? Gradient descent to the rescue," Games and Economic Behavior, Elsevier, vol. 123(C), pages 295-326.
- Yakov Babichenko, 2014. "How long to Pareto efficiency?," International Journal of Game Theory, Springer;Game Theory Society, vol. 43(1), pages 13-24, February.
- Babichenko, Yakov, 2013. "Best-reply dynamics in large binary-choice anonymous games," Games and Economic Behavior, Elsevier, vol. 81(C), pages 130-144.
- Babichenko, Yakov, 2012. "Completely uncoupled dynamics and Nash equilibria," Games and Economic Behavior, Elsevier, vol. 76(1), pages 1-14.
- Itai Arieli & H Peyton Young, 2011. "Stochastic Learning Dynamics and Speed of Convergence in Population Games," Economics Series Working Papers 570, University of Oxford, Department of Economics.
- Yakov Babichenko, 2018. "Fast Convergence of Best-Reply Dynamics in Aggregative Games," Mathematics of Operations Research, INFORMS, vol. 43(1), pages 333-346, February.
- Meir, Reshef & Kalai, Gil & Tennenholtz, Moshe, 2018. "Bidding games and efficient allocations," Games and Economic Behavior, Elsevier, vol. 112(C), pages 166-193.
- Jonathan Newton, 2018. "Evolutionary Game Theory: A Renaissance," Games, MDPI, vol. 9(2), pages 1-67, May.
- Babaioff, Moshe & Blumrosen, Liad & Schapira, Michael, 2013. "The communication burden of payment determination," Games and Economic Behavior, Elsevier, vol. 77(1), pages 153-167.
- Yakov Babichenko, 2012. "Best-Reply Dynamics in Large Anonymous Games," Discussion Paper Series dp600, The Federmann Center for the Study of Rationality, the Hebrew University, Jerusalem.
- Amir Danak & Shie Mannor, 2012. "Approximately optimal bidding policies for repeated first-price auctions," Annals of Operations Research, Springer, vol. 196(1), pages 189-199, July.
Most related items
These are the items that most often cite the same works as this one and are cited by the same works as this one.- Germano, Fabrizio & Lugosi, Gabor, 2007.
"Global Nash convergence of Foster and Young's regret testing,"
Games and Economic Behavior, Elsevier, vol. 60(1), pages 135-154, July.
- Fabrizio Germano & Gábor Lugosi, 2004. "Global Nash convergence of Foster and Young's regret testing," Economics Working Papers 788, Department of Economics and Business, Universitat Pompeu Fabra.
- Burkhard Schipper, 2015.
"Strategic teaching and learning in games,"
Working Papers
151, University of California, Davis, Department of Economics.
- Burkhard Schipper, 2017. "Strategic Teaching and Learning in Games," Working Papers 172, University of California, Davis, Department of Economics.
- Burkhard C. Schipper, 2022.
"Strategic Teaching and Learning in Games,"
American Economic Journal: Microeconomics, American Economic Association, vol. 14(3), pages 321-352, August.
- Burkhard Schipper, 2015. "Strategic teaching and learning in games," Working Papers 152, University of California, Davis, Department of Economics.
- Burkhard Schipper, 2017. "Strategic Teaching and Learning in Games," Working Papers 232, University of California, Davis, Department of Economics.
- Dean P Foster & Peyton Young, 2006. "Regret Testing Leads to Nash Equilibrium," Levine's Working Paper Archive 784828000000000676, David K. Levine.
- Sergiu Hart & Yishay Mansour, 2006.
"The Communication Complexity of Uncoupled Nash Equilibrium Procedures,"
Levine's Bibliography
122247000000001299, UCLA Department of Economics.
- Sergiu Hart & Yishay Mansour, 2006. "The Communication Complexity of Uncoupled Nash Equilibrium Procedures," Discussion Paper Series dp419, The Federmann Center for the Study of Rationality, the Hebrew University, Jerusalem.
- Vivaldo M. Mendes & Diana A. Mendes & Orlando Gomes, 2008. "Learning to Play Nash in Deterministic Uncoupled Dynamics," Working Papers Series 1 ercwp1808, ISCTE-IUL, Business Research Unit (BRU-IUL).
- H. Peyton Young, 2007. "The Possible and the Impossible in Multi-Agent Learning," Economics Series Working Papers 304, University of Oxford, Department of Economics.
- Foster, Dean P. & Hart, Sergiu, 2018.
"Smooth calibration, leaky forecasts, finite recall, and Nash dynamics,"
Games and Economic Behavior, Elsevier, vol. 109(C), pages 271-293.
- Dean P. Foster & Sergiu Hart, 2022. "Smooth Calibration, Leaky Forecasts, Finite Recall, and Nash Dynamics," Papers 2210.07152, arXiv.org.
- Sergiu Hart & Andreu Mas-Colell, 2013.
"Stochastic Uncoupled Dynamics And Nash Equilibrium,"
World Scientific Book Chapters, in: Simple Adaptive Strategies From Regret-Matching to Uncoupled Dynamics, chapter 8, pages 165-189,
World Scientific Publishing Co. Pte. Ltd..
- Hart, Sergiu & Mas-Colell, Andreu, 2006. "Stochastic uncoupled dynamics and Nash equilibrium," Games and Economic Behavior, Elsevier, vol. 57(2), pages 286-303, November.
- Sergiu Hart & Andreu Mas-Colell, 2004. "Stochastic uncoupled dynamics and Nash equilibrium," Economics Working Papers 783, Department of Economics and Business, Universitat Pompeu Fabra.
- Sergiu Hart & Andreu Mas-Colell, 2004. "Stochastic Uncoupled Dynamics and Nash Equilibrium," Levine's Bibliography 122247000000000466, UCLA Department of Economics.
- Sergiu Hart & Andreu Mas-Colell, 2004. "Stochastic Uncoupled Dynamics and Nash Equilibrium," Discussion Paper Series dp371, The Federmann Center for the Study of Rationality, the Hebrew University, Jerusalem.
- Sergiu Hart & Andreu Mas-Colell, 2004. "Stochastic Uncoupled Dynamics and Nash Equilibrium," Working Papers 174, Barcelona School of Economics.
- Tom Johnston & Michael Savery & Alex Scott & Bassel Tarbush, 2023. "Game Connectivity and Adaptive Dynamics," Papers 2309.10609, arXiv.org, revised Oct 2024.
- Marden, Jason R. & Shamma, Jeff S., 2015. "Game Theory and Distributed Control****Supported AFOSR/MURI projects #FA9550-09-1-0538 and #FA9530-12-1-0359 and ONR projects #N00014-09-1-0751 and #N0014-12-1-0643," Handbook of Game Theory with Economic Applications,, Elsevier.
- Young, H. Peyton, 2009. "Learning by trial and error," Games and Economic Behavior, Elsevier, vol. 65(2), pages 626-643, March.
- Rene Saran & Roberto Serrano, 2012.
"Regret Matching with Finite Memory,"
Dynamic Games and Applications, Springer, vol. 2(1), pages 160-175, March.
- Rene Saran & Roberto Serrano, 2010. "Regret Matching with Finite Memory," Levine's Working Paper Archive 661465000000000078, David K. Levine.
- Rene Saran & Roberto Serrano, 2010. "Regret matching with finite memory," Working Papers 2010-10, Instituto Madrileño de Estudios Avanzados (IMDEA) Ciencias Sociales.
- Saran, R.R.S. & Serrano, R., 2010. "Regret matching with finite memory," Research Memorandum 033, Maastricht University, Maastricht Research School of Economics of Technology and Organization (METEOR).
- Rene Saran & Roberto Serrano, 2010. "Regret Matching with Finite Memory," Working Papers 2010-10, Brown University, Department of Economics.
- Hart, Sergiu & Nisan, Noam, 2018.
"The query complexity of correlated equilibria,"
Games and Economic Behavior, Elsevier, vol. 108(C), pages 401-410.
- Sergiu Hart & Noam Nisan, 2013. "The Query Complexity of Correlated Equilibria," Levine's Working Paper Archive 786969000000000819, David K. Levine.
- Sergiu Hart & Noam Nisan, 2013. "The Query Complexity of Correlated Equilibria," Discussion Paper Series dp647, The Federmann Center for the Study of Rationality, the Hebrew University, Jerusalem.
- Sergiu Hart & Noam Nisan, 2013. "The Query Complexity of Correlated Equilibria," Papers 1305.4874, arXiv.org, revised Dec 2017.
- Hofbauer, Josef & Sandholm, William H., 2009. "Stable games and their dynamics," Journal of Economic Theory, Elsevier, vol. 144(4), pages 1665-1693.4, July.
- William Sandholm, 2014. "Probabilistic Interpretations of Integrability for Game Dynamics," Dynamic Games and Applications, Springer, vol. 4(1), pages 95-106, March.
- Michel Benaïm & Josef Hofbauer & Sylvain Sorin, 2006.
"Stochastic Approximations and Differential Inclusions, Part II: Applications,"
Mathematics of Operations Research, INFORMS, vol. 31(4), pages 673-695, November.
- Michel Benaïm & Josef Hofbauer & Sylvain Sorin, 2005. "Stochastic Approximations and Differential Inclusions; Part II: Applications," Working Papers hal-00242974, HAL.
- Babichenko, Yakov & Rubinstein, Aviad, 2022. "Communication complexity of approximate Nash equilibria," Games and Economic Behavior, Elsevier, vol. 134(C), pages 376-398.
- Jindani, Sam, 2022. "Learning efficient equilibria in repeated games," Journal of Economic Theory, Elsevier, vol. 205(C).
- Babichenko, Yakov, 2012. "Completely uncoupled dynamics and Nash equilibria," Games and Economic Behavior, Elsevier, vol. 76(1), pages 1-14.
More about this item
Keywords
Game Theory; Dynamics; Equilibrium; Nash Equilibrium; Correlated Equilibrium; Adaptive Dynamics; Simple Strategies; Regret-Based Strategies; Uncoupled Dynamics; Bounded Rationality;All these keywords.
JEL classification:
- C78 - Mathematical and Quantitative Methods - - Game Theory and Bargaining Theory - - - Bargaining Theory; Matching Theory
- C70 - Mathematical and Quantitative Methods - - Game Theory and Bargaining Theory - - - General
- C79 - Mathematical and Quantitative Methods - - Game Theory and Bargaining Theory - - - Other
Statistics
Access and download statisticsCorrections
All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:wsi:wschap:9789814390705_0010. See general information about how to correct material in RePEc.
If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.
If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .
If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.
For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Tai Tone Lim (email available below). General contact details of provider: http://www.worldscientific.com/page/worldscibooks .
Please note that corrections may take a couple of weeks to filter through the various RePEc services.