Generalized Kakeya sets for polynomial evaluation and faster computation of fermionants

Andreas Björklund, Petteri Kaski, Ryan Williams

Research output: Contribution to journalArticleScientificpeer-review

5 Citations (Scopus)
36 Downloads (Pure)


We present two new data structures for computing values of an n-variate polynomial P of degree at most d over a finite field of q elements. Assuming that d divides q−1, our first data structure relies on (d+1)n+2 tabulated values of P to produce the value of P at any of the qn points using O(nqd2) arithmetic operations in the finite field. Assuming that s divides d and d / s divides q−1, our second data structure assumes that P satisfies a degree-separability condition and relies on (d/s+1)n+s tabulated values to produce the value of P at any point using O(nqssq) arithmetic operations. Our data structures are based on generalizing upper-bound constructions due to Mockenhaupt and Tao (Duke Math J 121(1):35–74, 2004), Saraf and Sudan (Anal PDE 1(3):375–379, 2008) and Dvir (Incidence theorems and their applications, 2012. arXiv:1208.5073) for Kakeya sets in finite vector spaces from linear to higher-degree polynomial curves. As an application we show that the new data structures enable a faster algorithm for computing integer-valued fermionants, a family of self-reducible polynomial functions introduced by Chandrasekharan and Wiese (Partition functions of strongly correlated electron systems as fermionants, 2011. arXiv:1108.2461v1) that captures numerous fundamental algebraic and combinatorial functions such as the determinant, the permanent, the number of Hamiltonian cycles in a directed multigraph, as well as certain partition functions of strongly correlated electron systems in statistical physics. In particular, a corollary of our main theorem for fermionants is that the permanent of an m×m integer matrix with entries bounded in absolute value by a constant can be computed in time 2m−Ω(m/loglogm√), improving an earlier algorithm of Björklund (in: Proceedings of the 15th SWAT, vol 17, pp 1–11, 2016) that runs in time 2m−Ω(m/logm√).
Original languageEnglish
Pages (from-to)4010-4028
Issue number10
Publication statusPublished - 1 Oct 2019
MoE publication typeA1 Journal article-refereed


  • Besicovitch set
  • Fermionant
  • Finite field
  • Finite vector space
  • Hamiltonian cycle
  • Homogeneous polynomial
  • Kakeya set
  • Permanent
  • Polynomial evaluation
  • Tabulation


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