## Kin Chung Lo

Professor

**Office:** Vari Hall 1046

**Email:** kclo@yorku.ca

Kin Chung Lo is Professor of Economics at York University. He specializes in game theory and decision theory. His publications cover areas such as nonexpected utility, auctions, and foundations of solution concepts in games.

### Degrees

Ph.D. (Economics, under the supervision of Larry Epstein), University of TorontoM. Soc. Sc. (Economics), University of Hong Kong

B. Soc. Sc. (Economics, First Class Honors), University of Hong Kong

### Professional Leadership

Refereeing for American Economic Review, Bulletin of Economic Research, Econometrica, Economic Theory, Economics Bulletin, European Economic Review, Games and Economic Behavior, International Journal of Game Theory, Israel Science Foundation, Journal of Economic Theory, Journal of Mathematical Economics, McGraw-Hill Ryerson, Review of Economic Studies, Social Sciences and Humanities Research Council of Canada, Theoretical Economics, Theory and Decision.

### Research Interests

Possibility and Permissibility, *Mathematical Social Sciences*, 62 (2011), 109-113.

Correlated Nash Equilibrium, *Journal of Economic Theory*, 144 (2009), 722–743.

Risk, Ambiguity, and the Klibanoff Axioms, *Economics Bulletin*, 4 (2008), 1–5.

Sharing Beliefs about Actions, *Mathematical Social Sciences*, 53 (2007), 123–133.

A Robust Definition of Possibility for Biseparable Preferences, *Economics Bulletin*, 4 (2006), 1–7.

Agreement and Stochastic Independence of Belief Functions, *Mathematical Social Sciences*, 51 (2006), 1–22.

Likely Events and Possible States, *Topics in Theoretical Economics*, 5 (2005), Article 4.

More Likely than Unlikely, *Mathematical Social Sciences*, 49 (2005), 39–53.

Correlated Equilibrium under Uncertainty, *Mathematical Social Sciences*, 44 (2002), 183–209.

A Note on Mutually Absolutely Continuous Belief Systems, *Economics Letters*, 68 (2000), 149–156.

Agreement and Stochastic Independence of epsilon–Contaminated Beliefs, *Mathematical Social Sciences*, 39 (2000), 207–234.

Rationalizability and the Savage Axioms, *Economic Theory*, 15 (2000), 727–733.

Extensive Form Games with Uncertainty Averse Players, *Games and Economic Behavior*, 28 (1999), 256–270.

Nash Equilibrium without Mutual Knowledge of Rationality, *Economic Theory*, 14 (1999), 621–633.

Sealed Bid Auctions with Uncertainty Averse Bidders, *Economic Theory*, 12 (1998), 1–20 (lead article).

Equilibrium in Beliefs under Uncertainty, *Journal of Economic Theory*, 71 (1996), 443–484. Reprinted in *Uncertainty in Economic Theory—Essays in Honor of David Schmeidler’s 65th Birthday*, I. Gilboa, Ed., Routledge: London (2004), 483–521.

Weighted and Quadratic Models of Choice under Uncertainty, *Economics Letters*, 50 (1996), 381–386.

** Possibility and Permissibility**

* Mathematical Social Sciences * ,62 (2011), pp.109-113

**Abstract:** We formulate the permissibility concept (Brandenburger, 1992) in terms of general preference, and prove that the solution concept characterizes rationality, caution, and common "belief" of rationality and caution.

[go to paper]

** Correlated Nash Equilibrium **

* Journal of Economic Theory * , 144 (2009), pp.722-743

**Abstract:** We modify the epistemic conditions for Nash equilibrium only to accommodate Gilboa and Schmeidler's [I. Gilboa, D. Schmeidler, Maxmin expected utility with nonunique prior, J. Math. Econ. 18 (1989) 141-153] maxmin expected utility preferences, and identify the equilibrium concept in n-player strategic games that characterizes the modified epistemic conditions. The epistemic characterization supports the equilibrium concept as a minimal generalization of Nash equilibrium, in the sense that it deviates from Nash equilibrium only in terms of players' attitude towards ambiguity. Consequently, comparing it with Nash equilibrium constitutes a ceteris paribus study of the effects of ambiguity on how a game is played. For example, with ambiguity, (beliefs about) action choices are in general correlated.

[go to paper]

** Extensive Form Games with Uncertainty Averse Players**

* Games and Economic Behavior * , 28 (1999), pp.256-270

**Abstract:** Existing equilibrium concepts for games make use of the subjective expected utility model axiomatized by Savage (1954) to represent players' preferences. Accordingly, each player's beliefs about the strategies played by opponents are represented by a probability measure. Motivated by the Ellsberg Paradox and relevant experimental findings demonstrating that the beliefs of a decision maker may not be representable by a probability measure, this paper generalizes Nash Equilibrium in finite extensive form games to allow for preferences conforming to the multiple priors model developed in Gilboa and Schmeidler (1989). The implications of this generalization for strategy choices and welfare are studied.

[go to paper]

** Sealed Bid Auctions with Uncertainty Averse Bidders**

* Economic Theory * , 12 (1998), pp.1-20

**Abstract:** Traditional analysis of auctions assumes that each bidder's beliefs about opponents' valuations are represented by a probability measure. Motivated by experimental findings such as the Ellsberg Paradox, this paper examines the consequences of relaxing this assumption in the first and second price sealed bid auctions with independent private values. The multiple priors model of Gilboa and Schmeidler [Journal of Mathematical Economics, 18 (1989), 141-153] is adopted specifically to represent the bidders' (and the auctioneer's) preferences. The unique equilibrium bidding strategy in the first price auction is derived. Moreover, under an interesting parametric specialization of the model, it is shown that the first price auction Pareto dominates the second price auction.

[go to paper]

** Weighted and Quadratic Models of Choice under Uncertainty**

* Economics Letters * , 50 (1996), pp.381-386

**Abstract:** This paper extends the weighted and quadratic utility models of choice under risk to the context of choice under uncertainty. An important characteristic of the models is that they admit 'dynamically consistent' updating rules.

[go to paper]

** Equilibrium in Beliefs under Uncertainly**

* Journal of Economic Theory * , 71(2), 1996, pp.443-484

**Abstract:** Existing equilibrium concepts for games make use of the subjective expected utility model axiomatized by Savage (1954) to represent players' preferences. Accordingly, each player's beliefs about the strategies played by opponents are represented by a probability measure. Motivated by experimental findings such as the Ellsberg Paradox demonstrating that the beliefs of a decision maker may not be representable by a probability measure, this paper generalizes equilibrium concepts for normal form games to allow for the beliefs of each player to be representable by a closed and convex set of probability measures. The implications of this generalization for the strategy choices and welfare of players are studied.

[go to paper]

Kin Chung Lo is Professor of Economics at York University. He specializes in game theory and decision theory. His publications cover areas such as nonexpected utility, auctions, and foundations of solution concepts in games.

### Degrees

Ph.D. (Economics, under the supervision of Larry Epstein), University of TorontoM. Soc. Sc. (Economics), University of Hong Kong

B. Soc. Sc. (Economics, First Class Honors), University of Hong Kong

### Professional Leadership

Refereeing for American Economic Review, Bulletin of Economic Research, Econometrica, Economic Theory, Economics Bulletin, European Economic Review, Games and Economic Behavior, International Journal of Game Theory, Israel Science Foundation, Journal of Economic Theory, Journal of Mathematical Economics, McGraw-Hill Ryerson, Review of Economic Studies, Social Sciences and Humanities Research Council of Canada, Theoretical Economics, Theory and Decision.

### Research Interests

### All Publications

Possibility and Permissibility, *Mathematical Social Sciences*, 62 (2011), 109-113.

Correlated Nash Equilibrium, *Journal of Economic Theory*, 144 (2009), 722–743.

Risk, Ambiguity, and the Klibanoff Axioms, *Economics Bulletin*, 4 (2008), 1–5.

Sharing Beliefs about Actions, *Mathematical Social Sciences*, 53 (2007), 123–133.

A Robust Definition of Possibility for Biseparable Preferences, *Economics Bulletin*, 4 (2006), 1–7.

Agreement and Stochastic Independence of Belief Functions, *Mathematical Social Sciences*, 51 (2006), 1–22.

Likely Events and Possible States, *Topics in Theoretical Economics*, 5 (2005), Article 4.

More Likely than Unlikely, *Mathematical Social Sciences*, 49 (2005), 39–53.

Correlated Equilibrium under Uncertainty, *Mathematical Social Sciences*, 44 (2002), 183–209.

A Note on Mutually Absolutely Continuous Belief Systems, *Economics Letters*, 68 (2000), 149–156.

Agreement and Stochastic Independence of epsilon–Contaminated Beliefs, *Mathematical Social Sciences*, 39 (2000), 207–234.

Rationalizability and the Savage Axioms, *Economic Theory*, 15 (2000), 727–733.

Extensive Form Games with Uncertainty Averse Players, *Games and Economic Behavior*, 28 (1999), 256–270.

Nash Equilibrium without Mutual Knowledge of Rationality, *Economic Theory*, 14 (1999), 621–633.

Sealed Bid Auctions with Uncertainty Averse Bidders, *Economic Theory*, 12 (1998), 1–20 (lead article).

Equilibrium in Beliefs under Uncertainty, *Journal of Economic Theory*, 71 (1996), 443–484. Reprinted in *Uncertainty in Economic Theory—Essays in Honor of David Schmeidler’s 65th Birthday*, I. Gilboa, Ed., Routledge: London (2004), 483–521.

Weighted and Quadratic Models of Choice under Uncertainty, *Economics Letters*, 50 (1996), 381–386.

** Possibility and Permissibility**

* Mathematical Social Sciences * ,62 (2011), pp.109-113

**Abstract:** We formulate the permissibility concept (Brandenburger, 1992) in terms of general preference, and prove that the solution concept characterizes rationality, caution, and common "belief" of rationality and caution.

[go to paper]

** Correlated Nash Equilibrium **

* Journal of Economic Theory * , 144 (2009), pp.722-743

**Abstract:** We modify the epistemic conditions for Nash equilibrium only to accommodate Gilboa and Schmeidler's [I. Gilboa, D. Schmeidler, Maxmin expected utility with nonunique prior, J. Math. Econ. 18 (1989) 141-153] maxmin expected utility preferences, and identify the equilibrium concept in n-player strategic games that characterizes the modified epistemic conditions. The epistemic characterization supports the equilibrium concept as a minimal generalization of Nash equilibrium, in the sense that it deviates from Nash equilibrium only in terms of players' attitude towards ambiguity. Consequently, comparing it with Nash equilibrium constitutes a ceteris paribus study of the effects of ambiguity on how a game is played. For example, with ambiguity, (beliefs about) action choices are in general correlated.

[go to paper]

** Extensive Form Games with Uncertainty Averse Players**

* Games and Economic Behavior * , 28 (1999), pp.256-270

**Abstract:** Existing equilibrium concepts for games make use of the subjective expected utility model axiomatized by Savage (1954) to represent players' preferences. Accordingly, each player's beliefs about the strategies played by opponents are represented by a probability measure. Motivated by the Ellsberg Paradox and relevant experimental findings demonstrating that the beliefs of a decision maker may not be representable by a probability measure, this paper generalizes Nash Equilibrium in finite extensive form games to allow for preferences conforming to the multiple priors model developed in Gilboa and Schmeidler (1989). The implications of this generalization for strategy choices and welfare are studied.

[go to paper]

** Sealed Bid Auctions with Uncertainty Averse Bidders**

* Economic Theory * , 12 (1998), pp.1-20

**Abstract:** Traditional analysis of auctions assumes that each bidder's beliefs about opponents' valuations are represented by a probability measure. Motivated by experimental findings such as the Ellsberg Paradox, this paper examines the consequences of relaxing this assumption in the first and second price sealed bid auctions with independent private values. The multiple priors model of Gilboa and Schmeidler [Journal of Mathematical Economics, 18 (1989), 141-153] is adopted specifically to represent the bidders' (and the auctioneer's) preferences. The unique equilibrium bidding strategy in the first price auction is derived. Moreover, under an interesting parametric specialization of the model, it is shown that the first price auction Pareto dominates the second price auction.

[go to paper]

** Weighted and Quadratic Models of Choice under Uncertainty**

* Economics Letters * , 50 (1996), pp.381-386

**Abstract:** This paper extends the weighted and quadratic utility models of choice under risk to the context of choice under uncertainty. An important characteristic of the models is that they admit 'dynamically consistent' updating rules.

[go to paper]

** Equilibrium in Beliefs under Uncertainly**

* Journal of Economic Theory * , 71(2), 1996, pp.443-484

**Abstract:** Existing equilibrium concepts for games make use of the subjective expected utility model axiomatized by Savage (1954) to represent players' preferences. Accordingly, each player's beliefs about the strategies played by opponents are represented by a probability measure. Motivated by experimental findings such as the Ellsberg Paradox demonstrating that the beliefs of a decision maker may not be representable by a probability measure, this paper generalizes equilibrium concepts for normal form games to allow for the beliefs of each player to be representable by a closed and convex set of probability measures. The implications of this generalization for the strategy choices and welfare of players are studied.

[go to paper]