Abstract
We study the appearance of powers of Hamilton cycles in pseudorandom graphs, using the following comparatively weak pseudorandomness notion. A graph G is (ε,p,k,ℓ)-pseudorandom if for all disjoint X and Y ⊂ V(G) with |X|≥εp k n and |Y|≥εp ℓ n we have e(X,Y)=(1±ε)p|X||Y|. We prove that for all β>0 there is an ε>0 such that an (ε,p,1,2)-pseudorandom graph on n vertices with minimum degree at least βpn contains the square of a Hamilton cycle. In particular, this implies that (n,d,λ)-graphs with λ≪d 5/2 n -3/2 contain the square of a Hamilton cycle, and thus a triangle factor if n is a multiple of 3. This improves on a result of Krivelevich, Sudakov and Szabó [27].
We also extend our result to higher powers of Hamilton cycles and establish corresponding counting versions.
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P. Allen, J. Böttcher, H. Hàn, Y. Kohayakawa and Y. Person: Blow-up lemmas for sparse graphs, in preparation.
P. Allen, J. Böttcher, Y. Kohayakawa and Y. Person: Tight Hamilton cycles in random hypergraphs, Random Structures Algorithms, to appear (DOI: 10.1002/rsa.20519).
N. Alon: Explicit Ramsey graphs and orthonormal labelings, Electron. J. Combin. 1 (1994), Research Paper 12.
N. Alon and J. Bourgain: Additive patterns in multiplicative subgroups, Geom. Funct. Anal. 24 (2014), 721–739.
N. Alon and M. Capalbo: Sparse universal graphs for bounded-degree graphs, Random Structures Algorithms 31 (2007), 123–133.
N. Alon, M. Capalbo, Y. Kohayakawa, V. Rödl, A. Ruciński and E. Szemerédi: Universality and tolerance (extended abstract), in 41st Annual Symposium on Foundations of Computer Science (Redondo Beach, CA, 2000), 14–21. IEEE Comput. Soc. Press, Los Alamitos, CA, 2000.
N. Alon and J. H. Spencer: The probabilistic method, Wiley-Interscience Series in Discrete Mathematics and Optimization, John Wiley & Sons Inc., Hoboken, NJ, third edition, 2008, With an appendix on the life and work of Paul Erdős.
B. Bollobás: The evolution of sparse graphs, in: Graph theory and combinatorics (Cambridge, 1983), 35–57. Academic Press, London, 1984.
J. Böttcher, Y. Kohayakawa, A. Taraz and A. Würfl: An extension of the blow-up lemma to arrangeable graphs, arXiv:1305.2059, 2013.
F. Chung and R. Graham: Sparse quasi-random graphs, Combinatorica 22 (2002), 217–244.
F. R. K. Chung, R. L. Graham and R. M. Wilson: Quasi-random graphs, Combinatorica 9 (1989), 345–362.
S. M. Cioabă: Perfect matchings, eigenvalues and expansion, C. R. Math. Acad. Sci. Soc. R. Can. 27 (2005), 101–104.
D. Conlon: talk at RSA 2013.
D. Conlon, J. Fox and Y. Zhao: Extremal results in sparse pseudorandom graphs, Adv. Math. 256 (2014), 206–290.
C. Cooper and A. M. Frieze: On the number of Hamilton cycles in a random graph, J. Graph Theory 13 (1989), 719–735.
D. Dellamonica Jr., Y. Kohayakawa, V. Rödl and A. Ruciński: An improved upper bound on the density of universal random graphs, in: David Fernández-Baca, editor, LATIN 2012: Theoretical informatics (Arequipa, 2012), 231–242. Springer, 2012.
R. Glebov and M. Krivelevich: On the number of Hamilton cycles in sparse random graphs, SIAM J. Discrete Math. 27 (2013), 27–42.
S. Janson: The numbers of spanning trees, Hamilton cycles and perfect matchings in a random graph, Combin. Probab. Comput. 3 (1994), 97–126.
A. Johansson, J. Kahn and V. Vu: Factors in random graphs, Random Structures Algorithms 33 (2008), 1–28.
J. Komlós, G. N. Sárközy and E. Szemerédi: Blow-up lemma, Combinatorica 17 (1997), 109–123.
J. Komlós and E. Szemerédi: Limit distribution for the existence of Hamiltonian cycles in a random graph, Discrete Math. 43 (1983), 55–63.
A. D. Koršunov: Solution of a problem of P. Erdős and A. Rényi on Hamiltonian cycles in undirected graphs, Dokl. Akad. Nauk SSSR 228 (1976), 529–532.
A. D. Koršunov: Solution of a problem of P. Erdős and A. Rényi on Hamiltonian cycles in nonoriented graphs, Diskret. Analiz, (31 Metody Diskret. Anal. v Teorii Upravljajuscih Sistem) 90 (1977), 17–56.
M. Krivelevich: On the number of Hamilton cycles in pseudo-random graphs, Electron. J. Combin. 19 (2012), Paper 25.
M. Krivelevich and B. Sudakov: Sparse pseudo-random graphs are Hamiltonian, J. Graph Theory 42 (2003), 17–33.
M. Krivelevich and B. Sudakov: Pseudo-random graphs, in: More sets, graphs and numbers, volume 15 of Bolyai Soc. Math. Stud., 199–262. Springer, Berlin, 2006.
M. Krivelevich, B. Sudakov and T. Szabó: Triangle factors in sparse pseudorandom graphs, Combinatorica 24 (2004), 403–426.
D. Kühn and D. Osthus: On Pósa’s conjecture for random graphs, SIAM J. Discrete Math. 26 (2012), 1440–1457.
L. Pósa: Hamiltonian circuits in random graphs, Discrete Math. 14 (1976), 359–364.
O. Riordan: Spanning subgraphs of random graphs, Combin. Probab. Comput. 9 (2000), 125–148.
Z. W. Sun: Some new problems in additive combinatorics, arXiv:1309.1679, 2013.
A. Thomason: Pseudo-random graphs, in: Random graphs’ 85, Lect. 2nd Int. Semin., Poznań, Poland 1985, volume 33 of Ann. Discrete Math., 307–331, 1987.
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The cooperation of the authors was supported by a joint CAPES/DAAD project (415/ppp-probral/po/D08/11629, Proj. no. 333/09).
The authors are grateful to NUMEC/USP, Núcleo de Modelagem Estocástica e Complexidade of the University of São Paulo, and Project MaCLinC/USP, for supporting this research.
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Allen, P., Böttcher, J., Hàn, H. et al. Powers of Hamilton cycles in pseudorandom graphs. Combinatorica 37, 573–616 (2017). https://doi.org/10.1007/s00493-015-3228-2
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DOI: https://doi.org/10.1007/s00493-015-3228-2