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Papers maintained at the Arxiv

Journals Refereed: Annals of Combinatorics, Linear Algebra and Applications, Computational Geometry: Theory and Applications, Journal of Statistical Physics, American Mathematical Monthly, Proceedings of the American Mathematical Society, Mathematics of Computation, IEEE Transactions on Automatic Control, Monatshefte fur Mathematik

Collaborators: Scott Armstrong, Matthias Aschenbrenner, Luis Garcia, Charles R. Johnson, Aaron Lauve, Lionel Levine, Abraham Martin del Campo, Elchanan Mossel, Jiawang Nie, Yuval Peres, Maurice Rojas, Darren Rhea, Frank Sottile, Ilya Spitkovsky, Seth Sullevant, Troels Windfeldt.

(latest versions are always the pdf links)

In progress:

27.
(with A. Martin del Campo) Symmetric stabilization of toric ideals, in progress.

26.
(with S. Sullevant) Finitenss theorems for limits of invariant polynomial rings (or something like that anyway), in progress.

25.
(with M. Rojas) Sparse sums of squares, in progress.

24.
(with F. Sottile) Dynamic symmetric output feedback, in progress.

23.
Iterated Line Intersections of Rational Point-Sets in the Plane, in preparation. abstract

22. (with L. Garcia) Groebner bases and partial sums of Catalan numbers, in progress.

21.
(with M. Aschenbrenner) An algorithm to find Groebner bases of symmetric ideals in infinite dimensional polynomial rings, in preparation. IMA poster | Extended abstract | arxiv

20.
(with L. Levine) Word equations in groups with unique root extraction, in preparation.

19. (with A. Lauve) Uniqueness of binomial factorizations in group algebras, in progress. pdf (very early draft)



Published:

18.
Sums of polynomial squares over totally real fields are rational sums of squares, Proceedings of the American Mathematical Society, to appear. pdf

17. (with J. Nie) An elementary and constructive solution to Hilbert's 17th Problem for matrices, Proceedings of the American Mathematical Society, 136 (2008), 73-76. arxiv | pdf

16.
(with T. Windfeldt). An algebraic characterization of uniquely vertex colorable graphs, Journal of Combinatorial Theory Series B, 98 (2008), 400-414. pdf | arXiv | code

15.
(with T. Windfeldt). Minimal generators for symmetric ideals, Proceedings of the American Mathematical Society, 136 (2008), 4135-4137. arxiv | pdf

14.
(with S. Armstrong). Solvability of symmetric word equations in positive definite letters, Journal of the London Mathematical Society, 76 (2007), no. 3, 777-796. arXiv | pdf | maple code 1 | maple code 2

13. Advances on the Bessis-Moussa-Villani trace conjecture, Linear Algebra and Applications, 426 (2007), 130-142. arXiv | pdf | LinAlgAppl

12. (with L. Levine)  Polynomial recurrences and cyclic resultants, Proceedings of the American Mathematical Society, 135 (2007), 1607-1618.  arXiv | pdf | AMS

11. (with M. Aschenbrenner) Finite generation of symmetric ideals, Transactions of the American Mathematical Society, 359 (2007), 5171-5192.  arXiv | pdf

10. Cyclic Resultants, Journal of Symbolic Computation, 39 (2005), 653-669; erratum, ibid. 40 (2005), 1126–1127. arXiv | pdf | errata to print version

9. (with C. R. Johnson).  On the Positivity of the Coefficients of a Certain Polynomial Defined by Two Positive Definite Matrices, Journal of Statistical Physics, 118 (2005), 781-789. pdf | ps

8. (with D. L. Rhea).  A Result About the Density of Iterated Line Intersections in the Plane, Computational Geometry: Theory and Applications, 33 (2006), 106-114. arXiv (low res version) | pdf (high res version)

7. Appendix to the article "New Coins From Old: Computing With Unknown Bias," by E. Mossel and Y. Peres, Combinatorica, 25 (2005), 707-724. arXiv | pdf | ps

6. Logarithmic Derivatives of Solutions to Linear Differential Equations, Proceedings of the American Mathematical Society, 132 (2004), no. 9, 2693-2701. arXiv | pdf | ps | AMS (an expanded and more expository version is here).

5. (with C. R. Johnson).  Symmetric word equations in two positive definite letters, Proceedings of the American Mathematical Society 132 (2004), no. 4, 945-953. arXiv | pdf | ps

4. (with C. R. Johnson, Y. Harel, J. Groves, P. Rault). Absolutely Flat Idempotents, Electronic Journal of Linear Algebra, 10 (2003), pp. 190-200.  arxiv | pdf

3. (with C. R. Johnson).  Positive Eigenvalues of Generalized Words in Two Hermitian Positive Definite Matrices, in: Novel Approaches to Hard Discrete Optimization (P. Pardalos and H. Wolkowicz, eds.), Fields Institute Communications 37, 2003, pp. 111-122. arxiv | pdf

2. (with C. R. Johnson). Eigenvalues of Words in Two Positive Definite Letters, SIAM J. Matrix Anal. Appl., 23 (2002), pp. 916-928.  arxiv | SIAM | pdf

1. (with C. R. Johnson and I. M. Spitkovsky). Positive Eigenvalues and Two-letter Generalized Words, Electronic Journal of Linear Algebra, 9 (2002), pp. 21-26. arxiv | pdf


Other

5. (with T. Windfeldt). Fibonacci identities and graph colorings, Fibonaccci Quarterly, to appear. pdf | arXiv

4.
(with D. Rhea). Automorphisms of finite abelian groups, American Mathematical Monthly, 114 (2007), no. 10, 917-923. pdf | arXiv | Wikipedia

3. Uniqueness of degree 5 symmetric word equations. pdf

2. Relations between words in two positive definite letters. pdf | ps

1. University of California, Berkeley, Ph.D. Thesis, "Solving polynomial systems with special structure," 2005. pdf

Chris Hillar

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