Having a Hard Time? Explore Parameterized Complexity!

More often than not, life teems with difficult problems. This is not less true if you happen to be a researcher in computational social choice; however, in this case you can spend considerable time focusing only on computational hardness. Collective decision making has been studied from various aspects: political science, economy, mathematics, logic, and philosophy have all contributed to the area of social choce. With the advance of computer science, computational issues have become more and more important. Taking a casual look at the landscape of computational problems in social choice, we find an abundance of hard problems. Within the theory of voting, already winner determination is NP-hard for several electoral systems like Dodgson, Young, or Kemeny voting. Considering certain forms of manipulation, control, or bribery in elections, or dealing with partial information results in computationally hard problems as well. But we can find examples in every area of social choice, let it be judgment aggregation, auctions, fair division of goods, or matching under preferences.