Combinatorics on words
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Critical exponent of binary words with few distinct palindromes.
Lubomira Dvorakova, Pascal Ochem, and Daniela Opocenska.
Electron. J. Comb. 31(2) (2024), #P2.29.
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Pseudoperiodic words and a question of Shevelev.
Joseph Meleshko, Pascal Ochem, Jeffrey Shallit, and Sonja Linghui Shan.
DMTCS 25(2) (2023).
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Antisquares and critical exponents.
Aseem Baranwal, James Currie, Lucas Mol, Pascal Ochem, Narad Rampersad, and Jeffrey Shallit.
DMTCS 25(2) (2023).
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On ternary Dejean words avoiding 010.
Pascal Ochem.
NNTDM 29 (2023), 545-548.
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Properties of a ternary infinite word.
James Currie, Pascal Ochem, Narad Rampersad, and Jeffrey Shallit.
Theor. Informatics Appl. 57 (2023), 1.
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Doubled patterns with reversal and square-free doubled patterns.
Antoine Domenech and Pascal Ochem.
WORDS 2021.
Electron. J. Comb. 30(1) (2023), #P1.50.
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Avoiding square-free words on free groups.
Golnaz Badkobeh, Tero Harju, Pascal Ochem, and Matthieu Rosenfeld.
Theor. Comput. Sci. 922 (2022), 206-217.
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A family of formulas with reversal of arbitrarily high avoidability index.
Pascal Ochem.
Theor. Comput. Sci. 896 (2021), 168-170.
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Avoidability of palindrome patterns.
Pascal Ochem and Matthieu Rosenfeld.
Electron. J. Comb. 28(1) (2021), #P1.4.
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Avoiding conjugacy classes on the 5-letter alphabet.
Golnaz Badkobeh and Pascal Ochem.
Theor. Informatics Appl. 54 (2020), 2.
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On non-repetitive sequences of arithmetic progressions: the cases k ? {4, 5, 6, 7, 8}.
Borut Luzar, Martina Mockovciakova, Pascal Ochem, Alexandre Pinlou, and Roman Sotak.
Disc. Appl. Math. 279 (2020), 106-117.
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Some further results on squarefree arithmetic progressions in infinite words.
James Currie, Tero Harju, Pascal Ochem, and Narad Rampersad.
Theor. Comput. Sci. 799 (2019), 140-148.
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New results on pseudosquare avoidance.
Tim Ng, Pascal Ochem, Narad Rampersad, and Jeffrey Shallit.
WORDS 2019.
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Repetition avoidance in products of factors.
Pamela Fleischmann, Pascal Ochem, and Kamellia Reshadi.
Theor. Comput. Sci. 791 (2019), 123-126.
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On some interesting ternary formulas.
Pascal Ochem and Matthieu Rosenfeld.
WORDS 2017.
Electron. J. Comb. 26(1) (2019), #P1.12.
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On repetition thresholds of caterpillars and trees of bounded degree. Borut Luzar, Pascal Ochem, and Alexandre Pinlou.
Electron. J. Comb. 25(1) (2018), #P1.61.
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Avoidability of circular formulas. Guilhem Gamard, Pascal Ochem, Gwenael Richomme, and Patrice Seebold.
Theor. Comput. Sci. 726 (2018), 1-4.
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Avoidability of formulas with two variables.
Pascal Ochem and Matthieu Rosenfeld.
DLT 2016.
Electron. J. Comb. 24(4) (2017), #P4.30.
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A short proof that shuffle squares are 7-avoidable.
Guillaume Guegan and Pascal Ochem.
Theor. Informatics Appl. 50(1) (2016), 101-103.
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Doubled patterns are 3-avoidable.
Pascal Ochem.
Electron. J. Comb. 23(1) (2016), #P1.19.
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Characterization of some binary words with few squares.
Golnaz Badkobeh and Pascal Ochem.
Theor. Comput. Sci. 588 (2015), 73-80.
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Application of entropy compression in pattern avoidance.
Pascal Ochem and Alexandre Pinlou.
Electron. J. Comb. 21(2) (2014), #RP2.7.
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Binary patterns in binary cube-free words: avoidability and growth.
Robert Mercas, Pascal Ochem, Alexey Samsonov, and Arseny M. Shur.
Theor. Informatics Appl. 48(4) (2014), 369-389.
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More on square-free words obtained from prefixes by permutations.
Pascal Ochem.
Fundamenta Informaticae 132 (2014), 1-4.
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Repetition thresholds for subdivided graphs and trees.
Pascal Ochem and Elise Vaslet.
Theor. Informatics Appl. 46(1) (2012), 123-130.
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Thue choosability of trees.
Francesca Fiorenzi, Pascal Ochem, Patrice Ossona de Mendez, and Xuding Zhu.
Disc. Appl. Math. 159(17) (2011), 2045-2049.
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Bounds for the generalized repetition threshold.
Francesca Fiorenzi, Pascal Ochem, and Elise Vaslet.
Theor. Comput. Sci. 412 (2011), 2955-2963.
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On maximal repetitions of arbitrary exponent.
Roman Kolpakov, Gregory Kucherov, and Pascal Ochem.
Inform. Process. Lett. 110(7) (2010), 252-256.
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Binary words avoiding the pattern AABBCABBA.
Pascal Ochem.
Theor. Informatics Appl. 44 (1) (2010), 151-158.
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Minimum frequencies of occurrences of squares and letters in infinite words.
Pascal Ochem and Michael Rao.
Mons Days of Theoretical Computer Science. Mons, August 27 - 30 2008
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Unequal letter frequencies in ternary square-free words.
Pascal Ochem.
WORDS 2007. Marseille, September 17-21 2007
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Avoiding approximate squares.
Pascal Ochem, Narad Rampersad, and Jeffrey Shallit.
IJFCS 19 (3) (2008), 633-648.
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Dejean's conjecture and letter frequency.
Jeremie Chalopin and Pascal Ochem.
Mons Days of Theoretical Computer Science. Rennes, August 30 - September 2 2006
Theor. Informatics Appl. 42 (3) (2008), 477-480.
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Upper bound on the number of ternary square-free words.
Pascal Ochem and Tony Reix.
Workshop on Words and Automata. St Petersburg, June 7 2006
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Letter frequency in infinite repetition-free words.
Pascal Ochem. WORDS 2005. Montreal, September 13-17 2005.
Theor. Comput. Sci. 380 (2007), 388-392.
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A generator of morphisms for infinite words.
Pascal Ochem.
Word avoidability, complexity and morphisms. Turku, July 17 2004.
Theor. Informatics Appl. 40 (2006), 427-441.
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A generalization of repetition threshold.
Lucian Ilie, Pascal Ochem, and Jeffrey Shallit. MFCS 2004. Prague, August 22-27 2004.
Theor. Comput. Sci. 345 (2005), 359-369.
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How many square occurrences must a binary sequence contain ?
Gregory Kucherov, Pascal Ochem, and Michael Rao.
Electron. J. Comb. 10(1) (2003), #R12.
Graph theory
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Contact graphs of boxes with unidirectional contacts.
Daniel Goncalves, Vincent Limouzy, and Pascal Ochem.
DMTCS 25(3) (2024).
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Acyclic, star, and injective colouring: bounding the diameter.
Christoph Brause, Petr A. Golovach, Barnaby Martin, Pascal Ochem, Daniel Paulusma, and Siani Smith.
Electron. J. Comb. 29(2) (2022), #P2.43.
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Homomorphisms of planar (m,n)-colored-mixed graphs to planar targets.
Fabien Jacques and Pascal Ochem.
Discrete Math. 344(12) (2021), 112600.
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Partitioning sparse graphs into an independent set and a graph with bounded size components.
Ilkyoo Choi, Francois Dross, and Pascal Ochem.
Discrete Math. 343(8) (2020), 111921.
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Complexity of planar signed graph homomorphisms to cycles.
Francois Dross, Florent Foucaud, Valia Mitsou, Pascal Ochem, and Theo Pierron.
Disc. Appl. Math. 284 (2020), 166-178.
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Oriented cliques and colorings of graphs with low maximum degree.
Janusz Dybizbanski, Pascal Ochem, Alexandre Pinlou, and Andrzej Szepietowski.
Discrete Math. 343(5) (2020), 111829.
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Vertex partitions of (C3,C4,C6)-free planar graphs.
Francois Dross and Pascal Ochem.
Discrete Math. 342(11) (2019), 3229-3236.
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On the Konig-Egervary Theorem for k-Paths.
Stephane Bessy, Pascal Ochem, and Dieter Rautenbach.
J. Graph Theory 91(1) (2019), 73-87.
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Oriented incidence colourings of digraphs.
Christopher Duffy, Gary MacGillivray, Pascal Ochem, and Andre Raspaud.
Discussiones Mathematicae Graph Theory. 39 (2019), 191-210.
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2-subcoloring is NP-complete for planar comparability graphs. Pascal Ochem.
Inform. Process. Lett. 128 (2017), 46-48.
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Oriented, 2-edge-colored, and 2-vertex-colored homomorphisms. Nazanin Movarraei and Pascal Ochem.
Inform. Process. Lett. 123 (2017), 42-46.
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Exponential domination in subcubic graphs. Stephane Bessy, Pascal Ochem, and Dieter Rautenbach.
Electron. J. Comb. 23(4) (2016), #P4.42.
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The complexity of partitioning into disjoint cliques and a triangle-free graph. Marin Bougeret and Pascal Ochem.
Disc. Appl. Math. 217(3) (2017), 438-445.
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Bounds on the exponential domination number. Stephane Bessy, Pascal Ochem, and Dieter Rautenbach.
Discrete Math. 340(3) (2017), 494-503.
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Homomorphisms of 2-edge-colored triangle-free planar graphs. Pascal Ochem, Alexandre Pinlou, and Sagnik Sen.
J. Graph Theory 85(1) (2017), 258-277.
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Islands in graphs on surfaces. Louis Esperet and Pascal Ochem.
SIAM Journal on Discrete Mathematics 30(1) (2016), 206-219.
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On interval representations of graphs. Aquiles Braga De Queiroz, Valentin Garnero, and Pascal Ochem.
Disc. Appl. Math. 202 (2016), 30-36.
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Complexity dichotomy for oriented homomorphism of planar graphs with large girth. Guillaume Guegan and Pascal Ochem.
Theor. Comput. Sci. 596 (2015), 142-148.
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Near-colorings: non-colorable graphs and NP-completeness. Mickael Montassier and Pascal Ochem.
Electron. J. Comb. 22(1) (2015), #P1.57.
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The maximum clique problem in multiple interval graphs.
Mathew C. Francis, Daniel Goncalves, and Pascal Ochem. WG'2012, 57-68. Algorithmica 71(4) (2015), 812-836.
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Vertex-partitions of graphs into cographs and stars.
Paul Dorbec, Mickael Montassier, and Pascal Ochem.
J. Graph Theory 75(1) (2014), 75-90.
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Strong edge-colouring and induced matchings.
Herve Hocquard, Pascal Ochem, and Petru Valicov.
Inform. Process. Lett. 113(19-21) (2013), 836-843.
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A complexity dichotomy for the coloring of sparse graphs.
Louis Esperet, Mickael Montassier, Pascal Ochem, and Alexandre Pinlou.
J. Graph Theory 73(1) (2013), 85-102.
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Locally identifying coloring of graphs
Louis Esperet, Sylvain Gravier, Mickael Montassier, Pascal Ochem, and Aline Parreau.
Electron. J. Comb. 19(2) (2012), #P40.
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Oriented coloring of triangle-free planar graphs and 2-outerplanar graphs.
Pascal Ochem and Alexandre Pinlou.
LAGOS 2011, Bariloche, Argentina, March 28 - April 1st 2011.Graphs and Combinatorics 30(2) (2014), 439-453.
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Homomorphisms of 2-edge-colored graphs.
Amanda Montejano, Pascal Ochem, Alexandre Pinlou, Andre Raspaud, and Eric Sopena.
Disc. App. Math. 158(12) (2010), 1365-1379.
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Vertex decompositions of sparse graphs into an edgeless subgraph and a subgraph of maximum degree at most k.
Oleg V. Borodin, Anna O. Ivanova, Mickael Montassier, Pascal Ochem, and Andre Raspaud.
J. Graph Theory 65(2) (2010), 83-93.
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On star and caterpillar arboricity.
Daniel Goncalves and Pascal Ochem.
Discrete Math. 309(11) (2009), 3694-3702.
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On induced-universal graphs for the class of bounded-degree graphs.
Louis Esperet, Arnaud Labourel, and Pascal Ochem.
Inform. Process. Lett. 108(5) (2008), 255-260.
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Strong oriented chromatic number of planar graphs without short cycles.
Mickael Montassier, Pascal Ochem, and Alexandre Pinlou.
DMTCS 10(1) (2008).
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On the oriented chromatic index of oriented graphs.
Pascal Ochem, Alexandre Pinlou, and Eric Sopena.
J. Graph Theory 57(4) (2008), 313-332.
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On circle graphs with girth at least five.
Louis Esperet and Pascal Ochem. EuroComb 2007.
Seville, September 11-15 2007.
ENDM 29 (2007), 129-133.
Discrete Math. 309(8) (2009), 2217-2222.
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Oriented colorings of partial 2-trees.
Pascal Ochem and Alexandre Pinlou. EuroComb 2007.
Seville, September 11-15 2007.
ENDM 29 (2007), 195-199.
Inform. Process. Lett. 108(2) (2008), 82-86.
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Planar graphs have 1-string representations.
Jeremie Chalopin, Daniel Goncalves, and Pascal Ochem.
Discrete and Computational Geometry 43(3) (2010), 626-647.
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Oriented colorings of 2-outerplanar graphs.
Louis Esperet and Pascal Ochem.
Inform. Process. Lett. 101(5) (2006), 215-219.
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Negative results on acyclic improper colorings.
Pascal Ochem. EuroComb 2005.
Berlin, September 5-9 2005.
DMTCS Conference Volume AE (2005), 357-362.
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On the acyclic choosability of graphs.
Mickael Montassier, Pascal Ochem, and Andre Raspaud. Graph Theory 2004. Paris, July 5-9 2004
J. Graph Theory 51(4) (2006), 281-300.
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Oriented colorings of triangle-free planar graphs.
Pascal Ochem.
Inform. Process. Lett. 92(2) (2004), 71-76.
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On the interval number of special graphs.
Jozsef Balogh, Pascal Ochem, and Andras Pluhar.
J. Graph Theory 46(4) (2004), 241-253.
Odd perfect numbers
Programs and data for odd perfect numbers are here.
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Another remark on the radical of an odd perfect number. Pascal Ochem and Michael Rao.
The Fibonacci Quarterly 52(3) (2014), 215-217.
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On the number of prime factors of an odd perfect number. Pascal Ochem and Michael Rao.
Math. Comp. 83 (2014), 2435-2439.
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Odd perfect numbers are greater than 101500. Pascal Ochem and Michael Rao.
Math. Comp. 81 (2012), 1869-1877.
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Sieve methods for odd perfect numbers.
S. Adam Fletcher, Pace P. Nielsen, and Pascal Ochem.
Math. Comp. 81 (2012), 1753-1776.
Submitted manuscripts
thesis
Ph.D. Graph coloring and combinatorics on words.
HDR Evitement de motif.