# Dimitris Paparas

My name is Dimitris Paparas (Greek: Δημήτρης Παπάρας) and I am a theory PhD student at the Computer
Science department of Columbia University. My advisor is Prof. Mihalis Yannakakis.
Prior to that, I received a BSc in Computer Science and Telecommunications and a MSc in Theoretical Computer
Science, both from the Department of Informatics and Telecommunications of the
University of Athens, Greece. My supervisor was Prof. Elias Koutsoupias.

## Research Interests

My research lies in the area of Theoretical Computer Science. In particular, I am interested in the following topics:
- Algorithms
- Complexity Theory
- Computational Economics / Algorithmic Game Theory
- Optimization

My PhD focuses on Computational Economics with an emphasis on Equilibrium Computation. In particular, I am interested in algorithmic and complexity results regarding the computation of Arrow-Debreu and Fisher equilibrium in various settings. My goal is to understand whether there is a basic property that utility functions must have to allow polynomial time algorithms for finding an (approximate) equilibrium and whether finding an equilibrium is hard for utilities lacking this property. A closely related question is whether there exists a necessary and sufficient condition for utility functions to satisfy in order for the equilibrium to be expressed as a Convex Program, yielding polynomial time (approximation) algorithms. If you find these questions interesting, here is a related paper.

Finally, I am also interested in the related area of Algorithmic Mechanism Design. Specifically, I enjoy working on the problem of revenue maximization in various auction settings. Here is a related paper.

## Publications

*On the Complexity of Optimal Lottery Pricing and Randomized Mechanisms*, Xi Chen, Ilias Diakonikolas, Anthi Orfanou, Dimitris Paparas, Xiaorui Sun, Mihalis Yannakakis, FOCS 2015 [pdf coming soon]
*On-Line Profit-Maximization Algorithms for Managing Sponsored Content in Cellular Networks*, Matthew Andrews, Yigal Bejerano, Dimitris Paparas, Evangelia Skiani, 4th Smart Data Pricing (SDP) Workshop, 2015 [conference version]
*The Complexity of Optimal Multidimensional Pricing*, Xi Chen, Ilias Diakonikolas, Dimitris Paparas, Xiaorui Sun, Mihalis Yannakakis, SODA 2014 [arxiv, conference version]
*The Complexity of Non-Monotone Markets*, Xi Chen, Dimitris Paparas, Mihalis Yannakakis, STOC 2013 [arxiv, conference version]
*Clustering on k-Edge-Colored Graphs*, Eric Angel, Evripidis Bampis, Alexander Kononov, Dimitris Paparas, Emmanouil Pountourakis, Vassilis Zissimopoulos , MFCS 2013 [conference version]
*Flexible Use of Cloud Resources through Profit Maximization and Price Discrimination*, Konstantinos Tsakalozos, Herald Kllapi, Evangelia Sitaridi, Mema Roussopoulos, Dimitris Paparas, Alex Delis, ICDE 2011 [conference version]

## Contact

The best way to reach me is via e-mail at my_last_name@cs.columbia.edu