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Small Ball Probability for the Condition Number of Random Matrices

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Geometric Aspects of Functional Analysis

Abstract

Let A be an n × n random matrix with i.i.d. entries of zero mean, unit variance and a bounded sub-Gaussian moment. We show that the condition number \(s_{\max }(A)/s_{\min }(A)\) satisfies the small ball probability estimate

$$\displaystyle {\mathbb P}\big \{s_{\max }(A)/s_{\min }(A)\leq n/t\big \}\leq 2\exp (-c t^2),\quad t\geq 1, $$

where c > 0 may only depend on the sub-Gaussian moment. Although the estimate can be obtained as a combination of known results and techniques, it was not noticed in the literature before. As a key step of the proof, we apply estimates for the singular values of A, \({\mathbb P}\big \{s_{n-k+1}(A)\leq ck/\sqrt {n}\big \}\leq 2 \exp (-c k^2), \quad 1\leq k\leq n,\) obtained (under some additional assumptions) by Nguyen.

AMS 2010 Classification 60B20, 15B52, 46B06, 15A18

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References

  1. J.D. Batson, D.A. Spielman, N. Srivastava, Twice-Ramanujan sparsifiers, in Proceedings of the 2009 ACM International Symposium on Theory of Computing (STOC’09) (ACM, New York, 2009), pp. 255–262. MR2780071

    Google Scholar 

  2. J. Bourgain, L. Tzafriri, Invertibility of “large” submatrices with applications to the geometry of Banach spaces and harmonic analysis. Israel J. Math. 57(2), 137–224 (1987). MR0890420

    Google Scholar 

  3. N. Cook, Lower bounds for the smallest singular value of structured random matrices. Ann. Prob. (to appear). arXiv:1608.07347

    Google Scholar 

  4. A. Edelman, Eigenvalues and condition numbers of random matrices. SIAM J. Matrix Anal. Appl. 9(4), 543–560 (1988). MR0964668

    Google Scholar 

  5. D.L. Hanson, F.T. Wright, A bound on tail probabilities for quadratic forms in independent random variables. Ann. Math. Stat. 42, 1079–1083 (1971). MR0279864

    Google Scholar 

  6. A.E. Litvak, A. Pajor, M. Rudelson, N. Tomczak-Jaegermann, Smallest singular value of random matrices and geometry of random polytopes. Adv. Math. 195(2), 491–523 (2005). MR2146352

    Google Scholar 

  7. A.E. Litvak, A. Lytova, K. Tikhomirov, N. Tomczak-Jaegermann, P. Youssef, Adjacency matrices of random digraphs: singularity and anti-concentration. J. Math. Anal. Appl. 445(2), 1447–1491 (2017). MR3545253

    Google Scholar 

  8. A. Naor, P. Youssef, Restricted invertibility revisited, in A journey through discrete mathematics (Springer, Cham, 2017), pp. 657–691. MR3726618

    Google Scholar 

  9. H.H. Nguyen, Random matrices: overcrowding estimates for the spectrum. J. Funct. Anal. 275(8), 2197–2224 (2018). MR3841540

    Google Scholar 

  10. H.H. Nguyen, V.H. Vu, Normal vector of a random hyperplane. Int. Math. Res. Not. 2018(6), 1754–1778 (2018). MR3800634

    Google Scholar 

  11. M. Rudelson, K. Tikhomirov, The sparse circular law under minimal assumptions. Geom. Funct. Anal. 29(2), 561–637 (2019)

    Article  MathSciNet  Google Scholar 

  12. M. Rudelson, R. Vershynin, The Littlewood-Offord problem and invertibility of random matrices. Adv. Math. 218(2), 600–633 (2008). MR2407948

    Google Scholar 

  13. M. Rudelson, R. Vershynin, The least singular value of a random square matrix is O(n −1∕2). C. R. Math. Acad. Sci. Paris 346(15–16), 893–896 (2008). MR2441928

    Google Scholar 

  14. M. Rudelson, R. Vershynin, Smallest singular value of a random rectangular matrix. Commun. Pure Appl. Math. 62(12), 1707–1739 (2009). MR2569075

    Google Scholar 

  15. M. Rudelson, R. Vershynin, Hanson-Wright inequality and sub-Gaussian concentration. Electron. Commun. Probab. 18(82), 9 pp. (2013). MR3125258

    Google Scholar 

  16. M. Rudelson, R. Vershynin, No-gaps delocalization for general random matrices. Geom. Funct. Anal. 26(6), 1716–1776 (2016). MR3579707

    Google Scholar 

  17. D.A. Spielman, N. Srivastava, An elementary proof of the restricted invertibility theorem. Israel J. Math. 190, 83–91 (2012). MR2956233

    MathSciNet  MATH  Google Scholar 

  18. S.J. Szarek, Condition numbers of random matrices. J. Complexity 7(2), 131–149 (1991). MR1108773

    Google Scholar 

  19. T. Tao, Topics in random matrix theory. Graduate Studies in Mathematics, vol. 132 (American Mathematical Society, Providence, 2012)

    Google Scholar 

  20. T. Tao, V.H. Vu, Inverse Littlewood-Offord theorems and the condition number of random discrete matrices. Ann. Math. 169(2), 595–632 (2009). MR2480613

    Google Scholar 

  21. K. Tatarko, An upper bound on the smallest singular value of a square random matrix. J. Complexity 48, 119–128 (2018). MR3828841

    MathSciNet  MATH  Google Scholar 

  22. R. Vershynin, John’s decompositions: selecting a large part. Israel J. Math. 122, 253–277 (2001). MR1826503

    MathSciNet  MATH  Google Scholar 

  23. F.T. Wright, A bound on tail probabilities for quadratic forms in independent random variables whose distributions are not necessarily symmetric. Ann. Probab. 1(6), 1068–1070 (1973). MR0353419

    Google Scholar 

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Acknowledgements

The authors are grateful to the anonymous referee for careful reading and valuable suggestions that have helped to improve the presentation. The second named author would like to thank the Department of Mathematical and Statistical Sciences, University of Alberta for ideal working conditions.

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Litvak, A.E., Tikhomirov, K., Tomczak-Jaegermann, N. (2020). Small Ball Probability for the Condition Number of Random Matrices. In: Klartag, B., Milman, E. (eds) Geometric Aspects of Functional Analysis. Lecture Notes in Mathematics, vol 2266. Springer, Cham. https://doi.org/10.1007/978-3-030-46762-3_5

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