1.  Alonso, J., "Social security and retirement across the OECD"   Journal of Economic Dynamics & Control,  47 (2014) 300-316.


Employment to population ratios differ markedly across Organization for Economic Cooperation and Development (OECD) countries, especially for people aged over 55 years. In addition,social security features differ markedly across the OECD, particularly with respect tofeatures such as generosity, entitlementages,and implicit taxes on social security benefits. This study postulates that differences in social security features explain many differences in employment to population ratios at olderages. This conjecture is assessed quantitatively with a life cycle general equilibrium model of retirement. Atages 60–64years,the correlation between the simulation soft his study'smodel and observed data is0.67. Generosity and implicit taxes are keyfeatures to explain the cross-country variation, whereas entitlement age is not.

 2. Ülkü, L., "Implementation in an Interdependent Value Framework,"  Mathematical Social Sciences, 68-1 (2014): 64-78


We study ex post implementation in an interdependent value framework and with single dimensional types, using a class of mechanisms identified by monotonicity of outcomes and an integral representation of payments. We give examples to illustrate this class and its relation to the previous literature. The various extensions of the Vickrey-Clarke-Groves mechanism to interdependent value models are examples of this class. The extraction mechanisms of Crémer and McLean (1985) also form a special case for finite type spaces. The class is particularly useful in set allocation problems where the monotonicity condition is easier to work with.

3. Ülkü, L., "Mechanism design without monotone differences: an example featuring buyer habits,"  Economic Theory Bulletin, 2-2 (2014): 183-195.


Within a simple parametric example, I show that if the buyer’s values fail the monotone differences condition, nonmonotone mechanisms are not just feasible but may even be desirable for a seller. The failure of monotone differences is caused by intertemporal consumption externalities in the form of habits. I show that for an interval of habit parameters the revenue maximizing mechanism is nonmonotone: the seller screens out low and high types.