Activities

Publications and Awards

  • Reconfiguration of colorings in triangulations of the sphere

    Takehiro Ito, Yuni Iwamasa, Yusuke Kobayashi, Shun-ichi Maezawa, Yuta Nozaki, Yoshio Okamoto, Kenta Ozeki
    Proc. of 39th International Symposium on Computational Geometry (SoCG 2023), Leibniz International Proceedings in Informatics, Vol. 258, pp. 43:1-43:16, 2023

  • Sorting balls and water: Equivalence and computational complexity

    Takehiro Ito, Jun Kawahara, Shin-ichi Minato, Yota Otachi, Toshiki Saitoh, Akira Suzuki, Ryuhei Uehara, Takeaki Uno, Katsuhisa Yamanaka, Ryo Yoshinaka
    Theoretical Computer Science, Vol. 978, Article 114158, 2023

  • Algorithmic theory of qubit routing

    Takehiro Ito, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Yoshio Okamoto
    Proc. of 18th Algorithms and Data Structures Symposium (WADS 2023), Lecture Notes in Computer Science, Vol. 14079, pp. 533–546, 2023

  • On reachable assignments under dichotomous preferences

    Takehiro Ito, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Yuta Nozaki, Yoshio Okamoto, Kenta Ozeki
    Theoretical Computer Science, Vol. 979, Article 114196, 2023

  • Reconfiguration of spanning trees with degree constraints or diameter constraints

    Nicolas Bousquet, Takehiro Ito, Yusuke Kobayashi, Haruka Mizuta, Paul Ouvrard, Akira Suzuki, Kunihiro Wasa
    Algorithmica, Vol. 85, pp. 2779–2816, 2023

  • Fixed-parameter algorithms for graph constraint logic

    Tatsuhiko Hatanaka, Felix Hommelsheim, Takehiro Ito, Yusuke Kobayashi, Moritz Mühlenthaler, Akira Suzuki
    Theoretical Computer Science, Vol. 959, Article 113863, 2023

  • Reconfiguration and enumeration of optimal cyclic ladder lotteries

    Yuta Nozaki, Katsuhisa Yamanaka, Kunihiro Wasa
    Proc. of 34th International Workshop on Combinatorial Algorithms (IWOCA 2023), Lecture Notes in Computer Science, Vol. 13889, pp. 331-342, 2023

  • Rerouting planar curves and disjoint paths

    Takehiro Ito, Yuni Iwamasa, Naonori Kakimura, Yusuke Kobayashi, Shun-ichi Maezawa, Yuta Nozaki, Yoshio Okamoto, Kenta Ozeki
    Proc. of 50th EATCS International Colloquium on Automata, Languages and Programming (ICALP 2023), Leibniz International Proceedings in Informatics, Vol. 261, pp. 81:1-81:19, 2023

  • Polynomial-delay enumeration of large maximal common independent sets in two matroids

    Yasuaki Kobayashi, Kazuhiro Kurita, Kunihiro Wasa
    Proc. of 48th International Symposium on Mathematical Foundations of Computer Science (MFCS 2023), Leibniz International Proceedings in Informatics, Vol. 272, pp. 58:1-58:14, 2023

  • Reconfiguration of time-respecting arborescences

    Takehiro Ito, Yuni Iwamasa, Naoyuki Kamiyama, Yasuaki Kobayashi, Yusuke Kobayashi, Shun-ichi Maezawa, Akira Suzuki
    Proc. of 18th Algorithms and Data Structures Symposium (WADS 2023), Lecture Notes in Computer Science, Vol. 14079, pp. 521-532, 2023

  • Reconfiguration of vertex-disjoint shortest paths on graphs

    Rin Saito, Hiroshi Eto, Takehiro Ito, Ryuhei Uehara
    Proc. of 17th International Conference and Workshops on Algorithms and Computation (WALCOM 2023), Lecture Notes in Computer Science, Vol. 13973, pp. 191-201, 2023

  • Approximability of the distance independent set problem on regular graphs and planar graphs

    Hiroshi Eto, Takehiro Ito, Zhilong Liu, Eiji Miyano
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol. E105-A, pp. 1211-1222, 2022

  • Reconfiguration of cliques in a graph

    Takehiro Ito, Hirotaka Ono, Yota Otachi
    Discrete Applied Mathematics, Vol. 333, pp. 43-58, 2023

  • Sequentially swapping tokens: Further on graph classes

    Hironori Kiya, Yuto Okada, Hirotaka Ono, Yota Otachi
    Proc. of 48th International Conference on Current Trends in Theory and Practice of Computer Science (SOFSEM 2023), Lecture Notes in Computer Science, Vol. 13878, pp. 222-235, 2023

  • Extended MSO model checking via small vertex integrity

    Tatsuya Gima, Yota Otachi
    Proc. of 33rd International Symposium on Algorithms and Computation (ISAAC 2022), Leibniz International Proceedings in Informatics, Vol. 248, pp. 20:1-20:15, 2022

  • On reachable assignments under dichotomous preferences

    Takehiro Ito, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Yuta Nozaki, Yoshio Okamoto, Kenta Ozeki
    Proc. of 24th International Conference on Principles and Practice of Multi-Agent Systems (PRIMA 2022), Lecture Notes in Computer Science, Vol. 13753, pp. 650-658, 2022

  • Happy set problem on subclasses of co-comparability graphs

    Hiroshi Eto, Takehiro Ito, Eiji Miyano, Akira Suzuki, Yuma Tamura
    Algorithmica, Vol. 85, Article 44947, 2023

  • ZDD-based algorithmic framework for solving shortest reconfiguration problems

    Takehiro Ito, Jun Kawahara, Yu Nakahata, Takehide Soh, Akira Suzuki, Junichi Teruyama, Takahisa Toda
    Proc. of 20th International Conference on the Integration of Constraint Programming, Artificial Intelligence, and Operations Research (CPAIOR 2023), Lecture Notes in Computer Science, Vol. 13884, pp. 167-183, 2023

  • Monotone edge flips to an orientation of maximum edge-connectivity à la Nash-Williams

    Takehiro Ito, Yuni Iwamasa, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Shun-ichi Maezawa, Yuta Nozaki, Yoshio Okamoto, Kenta Ozeki
    ACM Transactions on Algorithms, Vol. 19, Article 6, 2023

  • A framework to design approximation algorithms for finding diverse solutions in combinatorial problems

    Tesshu Hanaka, Masashi Kiyomi, Yasuaki Kobayashi, Yusuke Kobayashi, Kazuhiro Kurita, Yota Otachi
    Proc. of 37th AAAI Conference on Artificial Intelligence (AAAI 2023), AAAI-23 Technical Tracks 4, Vol. 37, pp. 3968-3976, 2023

  • Reconfiguring (non-spanning) arborescences

    Takehiro Ito, Yuni Iwamasa, Yasuaki Kobayashi, Yu Nakahata, Yota Otachi, Kunihiro Wasa
    Theoretical Computer Science, Vol. 943, pp. 131-141, 2023

  • Sorting balls and water: Equivalence and computational complexity

    Takehiro Ito, Jun Kawahara, Shin-ichi Minato, Yota Otachi, Toshiki Saitoh, Akira Suzuki, Ryuhei Uehara, Takeaki Uno, Katsuhisa Yamanaka, Ryo Yoshinaka
    Proc. of 11th International Conference on Fun with Algorithms (FUN 2022), Leibniz International Proceedings in Informatics, Vol. 226, pp. 16:1-16:17, 2022

  • A parameterized view to the robust recoverable base problem of matroids under structural uncertainty

    Takehiro Ito, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Yoshio Okamoto
    Operations Research Letters, Vol. 50, pp. 370-375, 2022

  • An improved deterministic parameterized algorithm for cactus vertex deletion

    Yuuki Aoike, Tatsuya Gima, Tesshu Hanaka, Masashi Kiyomi, Yasuaki Kobayashi, Yusuke Kobayashi, Kazuhiro Kurita, Yota Otachi
    Theory of Computing Systems, Vol. 66, pp. 502-515, 2022

  • Parameterized complexity of non-separating and non-disconnecting paths and sets

    Ankit Abhinav, Susobhan Bandopadhyay, Aritra Banik, Yasuaki Kobayashi, Shunsuke Nagano, Yota Otachi, Saket Saurabh
    Proc. of 47th International Symposium on Mathematical Foundations of Computer Science (MFCS 2022), Leibniz International Proceedings in Informatics, Vol. 241, pp. 6:1-6:15, 2022

  • Algorithmic meta-theorems for combinatorial reconfiguration revisited

    Tatsuya Gima, Takehiro Ito, Yasuaki Kobayashi, Yota Otachi
    Proc. of 30th Annual European Symposium on Algorithms (ESA 2022), Leibniz International Proceedings in Informatics, Vol. 244, pp. 61:1-61:15, 2022

  • Polynomial-delay and polynomial-space enumeration of large maximal matchings

    Yasuaki Kobayashi, Kazuhiro Kurita, Kunihiro Wasa
    Proc. of 48th edition of the International Workshop on Graph-Theoretic Concepts in Computer Science (WG2022), Vol. 13453, pp. 342-355, 2022

  • Linear-delay enumeration for minimal Steiner problems

    Yasuaki Kobayashi, Kazuhiro Kurita, Kunihiro Wasa
    Proc. of 41st ACM SIGMOD-SIGACT-SIGAI Symposium on Principles of Database Systems (PODS 2022), pp. 301-313, 2022

  • Constant amortized time enumeration of Eulerian trails

    Kazuhiro Kurita, Kuniihiro Wasa
    Theoretical Computer Science, Vol. 923, Article 44573, 2022

  • Independent set reconfiguration on directed graphs

    Takehiro Ito, Yuni Iwamasa, Yasuaki Kobayashi, Yu Nakahata, Yota Otachi, Masahiro Takahashi, Kunihiro Wasa
    Proc. of 47th International Symposium on Mathematical Foundations of Computer Science, Leibniz International Proceedings in Informatics, Vol. 241, pp. 58:1-58:15, 2022

  • Shortest reconfiguration of perfect matchings via alternating cycles

    Takehiro Ito, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Yoshio Okamoto
    SIAM Journal on Discrete Mathematics, Vol. 36, pp. 1102-1123, 2022

  • Parameterized complexity of graph burning

    Yasuaki Kobayashi, Yota Otachi
    Algorithmica, Vol. 84, pp. 2379-2393, 2022

  • Monotone edge flips to an orientation of maximum edge-connectivity à la Nash-Williams

    Takehiro Ito, Yuni Iwamasa, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Shun-ichi Maezawa, Yuta Nozaki, Yoshio Okamoto, Kenta Ozeki
    Proc. of Annual ACM-SIAM Symposium on Discrete Algorithms (SODA 2022), pp. 1342-1355, 2022

  • Linear-time recognition of double-threshold graphs

    Yusuke Kobayashi, Yoshio Okamoto, Yota Otachi, Yushi Uno
    Algorithmica, Vol. 84, pp. 1163-1181, 2022

  • Reforming an envy-free matching

    Takehiro Ito, Yuni Iwamasa, Naonori Kakimura, Naoyuki Kamiyama, Yusuke Kobayashi, Yuta Nozaki, Yoshio Okamoto, Kenta Ozeki
    Proc. of 36th AAAI Conference on Artificial Intelligence (AAAI 2022), Vol. 36, pp. 5084-5091, 2022

  • Computing diverse shortest paths efficiently: A theoretical and experimental study

    Tesshu Hanaka, Yasuaki Kobayashi, Kazuhiro Kurita, See Woo Lee, Yota Otachi
    Proc. of 36th AAAI Conference on Artificial Intelligence (AAAI 2022), Vol. 36, pp. 3758-3766, 2022

  • Finding diverse trees, paths, and more

    Tesshu Hanaka, Yasuaki Kobayashi, Kazuhiro Kurita, Yota Otachi
    Proc. of the AAAI Conference on Artificial Intelligence (AAAI 2021), Vol. 35, pp. 3778-3786, 2021

  • IPSJ Yamashita SIG Research Award for FY2022

    WASA, Kunihiro (Hosei U.)
    "Constant Amortized Time Enumeration of Eulerian trails (2021-AL-183)"
    March 2, 2023

  • Parameterized complexity of (A, l)-path packing

    Rémy Belmonte, Tesshu Hanaka, Masaaki Kanzaki, Masashi Kiyomi, Yasuaki Kobayashi, Yusuke Kobayashi, Michael Lampis, Hirotaka Ono, Yota Otachi
    Algorithmica, Vol. 84, pp. 871-895, 2022

  • Reconfiguration of regular induced subgraphs

    Hiroshi Eto, Takehiro Ito, Yasuaki Kobayashi, Yota Otachi, Kunihiro Wasa
    Proc. of 16th International Conference and Workshops on Algorithms and Computation (WALCOM 2022), Lecture Notes in Computer Science, Vol. 13174, pp. 35-46, 2022

  • Happy set problem on subclasses of co-comparability graphs

    Hiroshi Eto, Takehiro Ito, Eiji Miyano, Akira Suzuki, Yuma Tamura
    Proc. of 16th International Conference and Workshops on Algorithms and Computation (WALCOM 2022), Lecture Notes in Computer Science, Vol. 13174, pp. 149-160, 2022

  • Reconfiguration of spanning trees with degree constraint or diameter constraint

    Nicolas Bousquet, Takehiro Ito, Yusuke Kobayashi, Haruka Mizuta, Paul Ouvrard, Akira Suzuki, Kunihiro Wasa
    Proc. of 39th International Symposium on Theoretical Aspects of Computer Science (STACS 2022), Leibniz International Proceedings in Informatics, Vol. 219, pp. 15:1-15:21, 2022

  • An O(n^2)-time algorithm for computing a max-min 3-dispersion on a point set in convex position

    Yasuaki Kobayashi, Shin-Ichi Nakano, Kei Uchizawa, Takeaki Uno, Yutaro Yamaguchi, Katsuhisa Yamanaka
    IEICE Transactions on Information and Systems, Vol. E105-D, pp. 503-507, 2022

  • On the security number of the Cartesian product of graphs

    Marko Jakovac, Yota Otachi
    Discrete Applied Mathematics, Vol. 304, pp. 119-128, 2021

  • Distributed reconfiguration of spanning trees

    Yukiko Yamauchi, Naoyuki Kamiyama, Yota Otachi
    Proc. of 23rd International Symposium on Stabilization, Safety, and Security of Distributed Systems (SSS 2021), Lecture Notes in Computer Science, Vol. 13046, pp. 516-520, 2021

  • Efficient enumeration of dominating sets for sparse graphs

    Kazuhiro Kurita, Kunihiro Wasa, Hiroki Arimura, Takeaki Uno
    Discrete Applied Mathematics, Vol. 303, pp. 283-295, 2021

  • Low-congestion shortcut and graph parameters

    Naoki Kitamura, Hirotaka Kitagawa, Yota Otachi, Taisuke Izumi
    Distributed Computing, Vol. 34, pp. 349-365, 2021

  • Computational complexity of jumping block puzzles

    Masaaki Kanzaki, Yota Otachi, Ryuhei Uehara
    Proc. of 27th International Computing and Combinatorics Conference (COCOON 2021), Lecture Notes in Computer Science, Vol. 13025, pp. 655-667, 2021

  • Reconfiguring directed trees in a digraph

    Takehiro Ito, Yuni Iwamasa, Yasuaki Kobayashi, Yu Nakahata, Yota Otachi, Kunihiro Wasa
    Proc. of 27th International Computing and Combinatorics Conference (COCOON 2021), Lecture Notes in Computer Science, Vol. 13025, pp. 343-354, 2021

  • Max-min 3-dispersion problems

    Takashi Horiyama, Shin-Ichi Nakano, Toshiki Saitoh, Koki Suetsugu, Akira Suzuki, Ryuhei Uehara, Takeaki Uno, Kunihiro Wasa
    IEICE Transactions on Fundamentals of Electronics, Communications and Computer Sciences, Vol. E104-A, pp. 1101-1107, 2021

  • Longest common subsequence in sublinear space

    Masashi Kiyomi, Takashi Horiyama, Yota Otachi
    Information Processing Letters, Vol. 168, pp. 106084, 2021

  • A constant amortized time enumeration algorithm for independent sets in graphs with bounded clique number

    Kazuhiro Kurita, Kunihiro Wasa, Takeaki Uno, Hiroki Arimura
    Theoretical Computer Science, Vol. 874, pp. 32-41, 2021

  • A (probably) optimal algorithm for bisection on bounded-treewidth graphs

    Tesshu Hanaka, Yasuaki Kobayashi, Taiga Sone
    Theoretical Computer Science, Vol. 873, pp. 38-46, 2021

  • Finding diverse trees, paths, and more

    Tesshu Hanaka, Yasuaki Kobayashi, Kazuhiro Kurita, Yota Otachi
    Proc. of the AAAI Conference on Artificial Intelligence (AAAI 2021), Vol. 35, pp. 3778-3786, 2021
    DOI: 

  • Algorithms for gerrymandering over graphs

    Takehiro Ito, Naoyuki Kamiyama, Yusuke Kobayashi, Yoshio Okamoto
    Theoretical Computer Science, Vol. 868, pp. 30-45, 2021

  • Exploring the gap between treedepth and vertex cover through vertex integrity

    Tatsuya Gima, Tesshu Hanaka, Masashi Kiyomi, Yasuaki Kobayashi, Yota Otachi
    Proc. of 12th International Conference on Algorithms and Complexity (CIAC 2021), Lecture Notes in Computer Science, Vol. 12701, pp. 271-285, 2021

  • Finding a maximum minimal separator: Graph classes and fixed-parameter tractability

    Tesshu Hanaka, Yasuaki Kobayashi, Yusuke Kobayashi, Tsuyoshi Yagita
    Theoretical Computer Science, Vol. 865, pp. 131-140, 2021

  • Optimal reconfiguration of optimal ladder lotteries

    Katsuhisa Yamanaka, Takashi Horiyama, Kunihiro Wasa
    Theoretical Computer Science, Vol. 859, pp. 57-69, 2021

  • Computing the largest bond and the maximum connected cut of a graph

    Gabriel L. Duarte, Hiroshi Eto, Tesshu Hanaka, Yasuaki Kobayashi, Yusuke Kobayashi, Daniel Lokshtanov, Lehilton L. C. Pedrosa, Rafael C. S. Schouery, Uéverton S. Souza
    Algorithmica, Vol. 83, pp. 1421-1458, 2021

  • Approximability of the independent feedback vertex set problem for bipartite graphs

    Yuma Tamura, Takehiro Ito, Xiao Zhou
    Theoretical Computer Science, Vol. 849, pp. 227-236, 2021

  • FIT2020 Funai Best Paper Award

    OKAMOTO, Yoshio (U. Electro-Communications), ITO, Takehiro (Tohoku U.), KAKIMURA, Naonori (Keio U.), KAMIYAMA, Naoyuki (Kyushu U.), KOBAYASHI, Yusuke (Kyoto U.)
    "Fixed-parameter algorithms for the robust recoverable base problem of matroids under structural uncertainty"
    August 26, 2021

  • 2021 JSAI Incentive Award, the Japanese Society for Artificial Intelligence

    HANAKA, Tesshu (Chuo U.), KOBAYASHI, Yasuaki (Kyoto U.), KURITA, Kazuhiro (National Institute of Informatics), OTACHI, Yota (Nagoya U.)
    "Algorithms for finding diverse subgraphs"
    June 21, 2021 (Affiliation at the time of the presentation)