Abstract
Let \(M\) be a \(C^{\infty }\) connected closed manifold with \(\mathrm{dim }(M)\ge 2\). Using tools developed by Körner in (J Lond Math Soc (2) 38(3):442–452, 1988) we prove that the subset of functions \(f\) in \(C^1(M,\mathbb R )\) such that the set of critical points of \(f\) is an arc is dense in \(C^{0}(M,\mathbb R )\). We then present applications in dynamics.
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References
Bates, S.M.: Toward a precise smoothness hypothesis in Sard’s theorem. Proc. Am. Math. Soc. 117(1), 279–283 (1993)
Fathi, A.: Partitions of unity for countable covers. Am. Math. Mon. 104(8), 720–723 (1997)
Fathi, A., Figalli, A., Rifford, L.: On the Hausdorff dimension of the Mather quotient. Commun. Pure Appl. Math. 62(4), 445–500 (2009)
Hurley, M.: Chain recurrence, semiflows, and gradients. J. Dyn. Differ. Equ. 7(3), 437–456 (1995)
Körner, T.W.: A dense arcwise connected set of critical points-molehills out of mountains. J. Lond. Math. Soc. (2) 38(3), 442–452 (1988)
Whitney, H.: A function not constant on a connected set of critical points. Duke Math. J. 1(4), 514–517 (1935)
Whitney, H.: Analytic extensions of differentiable functions defined in closed sets. Trans. Am. Math. Soc. 36(1), 63–89 (1934)
WesleyWilson Jr, F.: Smoothing derivatives of functions and applications. Trans. Am. Math. Soc. 139, 413–428 (1969)
Acknowledgments
The idea of this work came from a discussion with R. Deville who introduced the author to the work of Körner. The author also wants to thank T.W. Körner for sending a paper version of [5] and A. Fathi for his fruitfull comments and suggestions. Finally, the author thanks F. Laudenbach and M.Mazzucchelli who contributed to the final form of this paper. This work was supported by the ANR KAM faible (Project BLANC07-3-187245, Hamilton-Jacobi and Weak KAM theory).
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Pageault, P. Functions whose set of critical points is an arc. Math. Z. 275, 1121–1134 (2013). https://doi.org/10.1007/s00209-013-1173-6
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DOI: https://doi.org/10.1007/s00209-013-1173-6