16 citations · 27 across the 11 of their papers we have counts for
15 papers
On the Parallelizability of Approval-Based Committee Rules
Zack Fitzsimmons, Zohair Raza Hassan, Edith Hemaspaandra
Approval-Based Committee (ABC) rules are an important tool for choosing a fair set of candidates when given the preferences of a collection of voters. Though finding a winning comm…
On the Hardness of Fair Allocation under Ternary Valuations
Zack Fitzsimmons, Vignesh Viswanathan, Yair Zick
We study the problem of fair allocation of indivisible items when agents have ternary additive valuations -- each agent values each item at some fixed integer values , , or $…
Complexity of Conformant Election Manipulation
Zack Fitzsimmons, Edith Hemaspaandra
It is important to study how strategic agents can affect the outcome of an election. There has been a long line of research in the computational study of elections on the complexit…
Using Weighted Matching to Solve 2-Approval/Veto Control and Bribery
Zack Fitzsimmons, Edith Hemaspaandra
Determining the complexity of election attack problems is a major research direction in the computational study of voting problems. The paper "Towards completing the puzzle: comple…
Insight into Voting Problem Complexity Using Randomized Classes
Zack Fitzsimmons, Edith Hemaspaandra
The first step in classifying the complexity of an NP problem is typically showing the problem in P or NP-complete. This has been a successful first step for many problems, includi…
Kemeny Consensus Complexity
Zack Fitzsimmons, Edith Hemaspaandra
The computational study of election problems generally focuses on questions related to the winner or set of winners of an election. But social preference functions such as Kemeny r…
Representative Proxy Voting
Elliot Anshelevich, Zack Fitzsimmons, Rohit Vaish +1
We study a model of proxy voting where the candidates, voters, and proxies are all located on the real line, and instead of voting directly, each voter delegates its vote to the cl…
Selecting Voting Locations for Fun and Profit
Zack Fitzsimmons, Omer Lev
While manipulative attacks on elections have been well-studied, only recently has attention turned to attacks that account for geographic information, which are extremely common in…
Very Hard Electoral Control Problems
Zack Fitzsimmons, Edith Hemaspaandra, Alexander Hoover +1
It is important to understand how the outcome of an election can be modified by an agent with control over the structure of the election. Electoral control has been studied for man…
Election Score Can Be Harder Than Winner
Zack Fitzsimmons, Edith Hemaspaandra
Election systems based on scores generally determine the winner by computing the score of each candidate and the winner is the candidate with the best score. It would be natural to…
High-Multiplicity Election Problems
Zack Fitzsimmons, Edith Hemaspaandra
The computational study of elections generally assumes that the preferences of the electorate come in as a list of votes. Depending on the context, it may be much more natural to r…
Modeling Single-Peakedness for Votes with Ties
Zack Fitzsimmons, Edith Hemaspaandra
Single-peakedness is one of the most important and well-known domain restrictions on preferences. The computational study of single-peaked electorates has largely been restricted t…
Complexity of Manipulative Actions When Voting with Ties
Zack Fitzsimmons, Edith Hemaspaandra
Most of the computational study of election problems has assumed that each voter's preferences are, or should be extended to, a total order. However in practice voters may have pre…
Single-Peaked Consistency for Weak Orders Is Easy
Zack Fitzsimmons
In economics and social choice single-peakedness is one of the most important and commonly studied models for preferences. It is well known that single-peaked consistency for total…
X THEN X: Manipulation of Same-System Runoff Elections
Zack Fitzsimmons, Edith Hemaspaandra, Lane A. Hemaspaandra
Do runoff elections, using the same voting rule as the initial election but just on the winning candidates, increase or decrease the complexity of manipulation? Does allowing revot…