A numeral system for the middle-levels graphs

A sequence S of restricted-growth strings unifies the presentation of middle-levels graphs Mk as follows, for 0 < k ∈ Z. Recall Mk is the subgraph in the Hasse diagram of the Boolean lattice 2[2k+1] induced by the k- and (k+1)-levels. The dihedral group D4k+2 acts on Mk via translations mod (2k +...

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Main Author: Dejter, Italo J.; University of Puerto Rico Rio Piedras, PR 0936-8377 (Author)
Format: EJournal Article
Published: GTA Research Group, Univ. Newcastle, Indonesian Combinatorics Society and ITB, 2021-04-15.
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LEADER 02070 am a22002533u 4500
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042 |a dc 
100 1 0 |a Dejter, Italo J.; University of Puerto Rico Rio Piedras, PR  |d 0936-8377.   |e author 
100 1 0 |e contributor 
245 0 0 |a A numeral system for the middle-levels graphs 
260 |b GTA Research Group, Univ. Newcastle, Indonesian Combinatorics Society and ITB,   |c 2021-04-15. 
500 |a https://www.ejgta.org/index.php/ejgta/article/view/613 
520 |a A sequence S of restricted-growth strings unifies the presentation of middle-levels graphs Mk as follows, for 0 < k ∈ Z. Recall Mk is the subgraph in the Hasse diagram of the Boolean lattice 2[2k+1] induced by the k- and (k+1)-levels. The dihedral group D4k+2 acts on Mk via translations mod (2k + 1) and complemented reversals.The first (2k)!/(k!(k+1)!) terms of S stand for the orbits of V(Mk) under such D4k+2-action, via the lexical matching colors 0, 1, ... , k on the k+1 edges at each vertex. So, S is proposed here as a convenient numeral system for the graphs Mk. Color 0 allows to reorder S via an integer sequence that behaves as an idempotent permutation on its first (2k)!/(k!(k+1)!) terms, for each 0 < k ∈ Z. Related properties hold for the remaining colors 1, ... , k. 
540 |a Copyright (c) 2021 Electronic Journal of Graph Theory and Applications (EJGTA) 
546 |a eng 
690 |a numeral system, middle-levels graph, Boolean lattice, Hasse diagram, complemented reversal 
690 |a 05C62, 05C75, 06A05, 05C69, 05C45 
655 7 |a info:eu-repo/semantics/article  |2 local 
655 7 |a info:eu-repo/semantics/publishedVersion  |2 local 
655 7 |a Peer-reviewed Article  |2 local 
786 0 |n Electronic Journal of Graph Theory and Applications (EJGTA); Vol 9, No 1 (2021): Electronic Journal of Graph Theory and Applications; 137 - 156 
786 0 |n 2338-2287 
787 0 |n https://www.ejgta.org/index.php/ejgta/article/view/613/pdf_168 
856 4 1 |u https://www.ejgta.org/index.php/ejgta/article/view/613/pdf_168  |z Get Fulltext