K
Kei Uchizawa
Researcher at Yamagata University
Publications - 42
Citations - 368
Kei Uchizawa is an academic researcher from Yamagata University. The author has contributed to research in topics: Boolean function & Upper and lower bounds. The author has an hindex of 8, co-authored 40 publications receiving 319 citations. Previous affiliations of Kei Uchizawa include Tohoku University.
Papers
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Journal ArticleDOI
Swapping labeled tokens on graphs
Katsuhisa Yamanaka,Erik D. Demaine,Takehiro Ito,Jun Kawahara,Masashi Kiyomi,Yoshio Okamoto,Toshiki Saitoh,Akira Suzuki,Kei Uchizawa,Takeaki Uno +9 more
TL;DR: It is proved that every such puzzle is solvable in O ( n 2 ) token swaps, and thus the problem of minimizing the number of token swaps to reach the target token placement can be solved exactly in polynomial time on complete bipartite graphs.
Journal ArticleDOI
On the Rainbow Connectivity of Graphs: Complexity and FPT Algorithms
TL;DR: The precise computational complexities of all the three problems with regards to graph diameters are settled, and the FPT algorithms imply that all the problems can be solved in polynomial time for any graph with n vertices if |C|=O(logn).
Journal ArticleDOI
On the computational power of threshold circuits with sparse activity
TL;DR: This letter investigates a new complexity measure for threshold circuits, energy complexity, whose minimization yields computations with sparse activity, and proves that all computations by threshold circuits of polynomial size with entropy O(log n) can be restructured so that their energy complexity is reduced to a level near the entropy of circuit states.
Book ChapterDOI
Swapping Labeled Tokens on Graphs
Katsuhisa Yamanaka,Erik D. Demaine,Takehiro Ito,Jun Kawahara,Masashi Kiyomi,Yoshio Okamoto,Toshiki Saitoh,Akira Suzuki,Kei Uchizawa,Takeaki Uno +9 more
TL;DR: It is proved that every puzzle is solvable in O(n 2) token swaps, and the problem of minimizing the number of token swaps to reach the target token placement can be solved exactly in polynomial time on complete bipartite graphs.
Journal ArticleDOI
Exponential lower bounds on the size of constant-depth threshold circuits with small energy complexity
Kei Uchizawa,Eiji Takimoto +1 more
TL;DR: It is shown that there exists a trade-off among three complexity measures of threshold circuits: the energy complexity, size, and depth, which implies an exponential lower bound on the size of constant-depth threshold circuits with small energy complexity for a large class of Boolean functions.