Counting Complexity Classes for Numeric Computations I: Semilinear Sets

  • Authors:
  • Peter Bürgisser;Felipe Cucker

  • Affiliations:
  • -;-

  • Venue:
  • SIAM Journal on Computing
  • Year:
  • 2004

Quantified Score

Hi-index 0.00

Visualization

Abstract

We define a counting class ${\rm \#P}_\add$ in the Blum--Shub--Smale setting of additive computations over the reals. Structural properties of this class are studied, including a characterization in terms of the classical counting class $\#{\sf P}$ introduced by Valiant. We also establish transfer theorems for both directions between the real additive and the discrete setting. Then we characterize in terms of completeness results the complexity of computing basic topological invariants of semilinear sets given by additive circuits. It turns out that the computation of the Euler characteristic is ${\rm FP}_{\rm add}^{{\rm \#P}_{\rm add}}$-complete, while for fixed $k$ the computation of the $k$th Betti number is ${\rm FPAR}_{\rm add}$-complete. Thus the latter is more difficult under standard complexity theoretic assumptions. We use all of the above to prove some analogous completeness results in the classical setting.