Barriers to Manipulation in Voting

Introduction to Computational Social Choice

“…Even if option C had not been removed, the supporters of C could have manipulated the election by pretending that they support B rather than C, thereby ensuring a preferred outcome, namely B rather than A. Manipulation is discussed in depth in Chapters 2 (Zwicker, 2016) and 6 (Conitzer and Walsh, 2016).…”

“…The role of randomization as a barrier to strategic behavior is discussed in Chapter 6 (Conitzer and Walsh, 2016). Depending on how preferences over probability distributions are defined, one can define various degrees of strategyproofness, economic efficiency, and participation.…”

Matching under Preferences

“…This approach is typical in voting theory, which is the subject of Chapter 6 (Conitzer and Walsh, 2015) on Barriers to Manipulation, since no voting rule is strategy-proof (Arrow et al, 2002;Bartholdi et al, 1989). It is possible to exploit such results to define stable mechanisms that are resistant to strategic behaviour.…”

Judgment Aggregation

“…As discussed in depth in Chapter 6 (Conitzer and Walsh, 2016), for aggregators that are not immune to manipulation a relevant question is whether it may be the case that manipulation is a computationally intractable problem, as this may provide at least some level of protection against unwanted strategic behavior. The manipulation problem for a given aggregator f and a given method of deriving preferences from judgment sets is the problem of deciding whether a judge may obtain a preferred outcome by misreporting her judgment set.…”