# Smale's problems

Smale's problems are a list of eighteen unsolved problems in mathematics that was proposed by Steve Smale in 1998,[1] republished in 1999.[2] Smale composed this list in reply to a request from Vladimir Arnold, then president of the International Mathematical Union, who asked several mathematicians to propose a list of problems for the 21st century. Arnold's inspiration came from the list of Hilbert's problems that had been published at the beginning of the 20th century.

## List of problems

# Formulation Status
2 Poincaré conjecture Proved by Grigori Perelman in 2003 using Ricci flow.[3][4][5]
3 Does P = NP?
4 Shub–Smale τ-conjecture on the integer zeros of a polynomial of one variable[6][7]
5 Height bounds for Diophantine curves
6 Finiteness of the number of relative equilibria in celestial mechanics Proved for five bodies by A. Albouy and V. Kaloshin in 2012.[8]
7 Distribution of points on the 2-sphere A noteworthy form of this problem is the Thomson Problem of equal point charges on a unit sphere governed by the electrostatic Coulomb's law. Very few exact N-point solutions are known while most solutions are numerical. Numerical solutions to this problem have been shown to correspond well with features of electron shell-filling in Atomic structure found throughout the periodic table.[9] A well-defined, intermediate step to this problem involving a point charge at the origin has been reported.[10]
8 Introduction of dynamics into economic theory
9 The linear programming problem: find a strongly-polynomial time algorithm which for given matrix A ∈ Rm×n and b ∈ Rm decides whether there exists x ∈ Rn with Ax ≥ b.
10 Pugh's closing lemma (higher order of smoothness)
11 Is one-dimensional dynamics generally hyperbolic?
12 Centralizers of diffeomorphisms Solved in the C1 topology by C. Bonatti, S. Crovisier and Amie Wilkinson[11] in 2009.
13 Hilbert's 16th problem
14 Lorenz attractor Solved by Warwick Tucker in 2002 using interval arithmetic.[12]
15 Do the Navier–Stokes equations in R3 always have a unique smooth solution that extends for all time?
16 Jacobian conjecture (equivalently, Dixmier conjecture)
17 Solving polynomial equations in polynomial time in the average case C. Beltrán and L. M. Pardo found a uniform probabilistic algorithm (average Las Vegas algorithm) for Smale's 17th problem.[13][14] A deterministic algorithm for Smale's 17th problem has not been found yet, but a partial answer has been given by F. Cucker and P. Bürgisser who proceeded to the smoothed analysis of a probabilistic algorithm à la Beltrán-Pardo, and then exhibited a deterministic algorithm running in time $N^{O(\log\log N)}$.[15]
18 Limits of intelligence

## References

1. ^ Steve Smale (1998). "Mathematical Problems for the Next Century". Mathematical Intelligencer 20 (2): 7–15. doi:10.1007/bf03025291.
2. ^ Steve Smale (1999). "Mathematical problems for the next century". In V. I. Arnold, M. Atiyah, P. Lax, B. Mazur. Mathematics: frontiers and perspectives. American Mathematical Society. pp. 271–294. ISBN 0821820702.
3. ^ Perelman, Grigori (2002). "The entropy formula for the Ricci flow and its geometric applications". arXiv:math.DG/0211159 [math.DG].
4. ^ Perelman, Grigori (2003). "Ricci flow with surgery on three-manifolds". arXiv:math.DG/0303109 [math.DG].
5. ^ Perelman, Grigori (2003). "Finite extinction time for the solutions to the Ricci flow on certain three-manifolds". arXiv:math.DG/0307245 [math.DG].
6. ^ Shub, Michael; Smale, Steve (1995). "On the intractability of Hilbert’s Nullstellensatz and an algebraic version of “NP≠P?”". Duke Math. J. 81: 47–54. doi:10.1215/S0012-7094-95-08105-8. Zbl 0882.03040.
7. ^ Bürgisser, Peter (2000). Completeness and reduction in algebraic complexity theory. Algorithms and Computation in Mathematics 7. Berlin: Springer-Verlag. p. 141. ISBN 3-540-66752-0. Zbl 0948.68082.
8. ^ A. Albouy, V. Kaloshin (2012). "Finiteness of central configurations of five bodies in the plane". Annals of Mathematics 176: 535–588. doi:10.4007/annals.2012.176.1.10.
9. ^ T. LaFave Jr (2013). "Correspondences between the classical electrostatic Thomson Problem and atomic electronic structure". Journal of Electrostatics 71 (6): 1029–1035. doi:10.1016/j.elstat.2013.10.001. Retrieved 11 Feb 2014.
10. ^ T. LaFave Jr (2014). "Discrete transformations in the Thomson Problem". Journal of Electrostatics 72 (1): 39–43. doi:10.1016/j.elstat.2013.11.007. Retrieved 11 Feb 2014.
11. ^ C. Bonatti, S. Crovisier, A. Wilkinson (2009). "The C1-generic diffeomorphism has trivial centralizer". Publications Mathématiques de l'IHÉS 109: 185–244. doi:10.1007/s10240-009-0021-z.
12. ^ Warwick Tucker (2002). "A Rigorous ODE Solver and Smale's 14th Problem". Foundations of Computational Mathematics 2 (1): 53–117. doi:10.1007/s002080010018.
13. ^ Carlos Beltrán, Luis Miguel Pardo (2008). "On Smale's 17th Problem: A Probabilistic Positive answer". Foundations of Computational Mathematics 8 (1): 1–43. doi:10.1007/s10208-005-0211-0.
14. ^ Carlos Beltrán, Luis Miguel Pardo (2009). "Smale's 17th Problem: Average Polynomial Time to compute affine and projective solutions". Journal of the American Mathematical Society 22: 363–385. doi:10.1090/s0894-0347-08-00630-9.
15. ^ Felipe Cucker, Peter Bürgisser (2011). "On a problem posed by Steve Smale". Annals of Mathematics 174 (3): 1785–1836. doi:10.4007/annals.2011.174.3.8.