Random generation of combinatorial structures from a uniform
Theoretical Computer Science
The complexity of counting graph homomorphisms
Proceedings of the ninth international conference on on Random structures and algorithms
A dichotomy theorem for constraint satisfaction problems on a 3-element set
Journal of the ACM (JACM)
Counting independent sets up to the tree threshold
Proceedings of the thirty-eighth annual ACM symposium on Theory of computing
The complexity of partition functions
Theoretical Computer Science - Automata, languages and programming: Algorithms and complexity (ICALP-A 2004)
The roots of the independence polynomial of a clawfree graph
Journal of Combinatorial Theory Series B
Computational Complexity: A Modern Approach
Computational Complexity: A Modern Approach
Computational Transition at the Uniqueness Threshold
FOCS '10 Proceedings of the 2010 IEEE 51st Annual Symposium on Foundations of Computer Science
A Complexity Dichotomy for Partition Functions with Mixed Signs
SIAM Journal on Computing
Complexity of counting CSP with complex weights
STOC '12 Proceedings of the forty-fourth annual ACM symposium on Theory of computing
The Computational Hardness of Counting in Two-Spin Models on d-Regular Graphs
FOCS '12 Proceedings of the 2012 IEEE 53rd Annual Symposium on Foundations of Computer Science
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We study the complexity of computing average quantities related to spin systems, such as the mean magnetization and susceptibility in the ferromagnetic Ising model, and the average dimer count (or average size of a matching) in the monomer-dimer model. By establishing connections between the complexity of computing these averages and the location of the complex zeros of the partition function, we show that these averages are #P-hard to compute. In case of the Ising model, our approach requires us to prove an extension of the famous Lee-Yang Theorem from the 1950s.