SHILLA GRAPHS WITH \(b=5\) AND \(b=6\)

A \(Q\)-polynomial Shilla graph with \(b = 5\) has intersection arrays \(\{105t,4(21t+1),16(t+1); 1,4 (t+1),84t\}\), \(t\in\{3,4,19\}\). The paper proves that distance-regular graphs with these intersection arrays do not exist. Moreover, feasible intersection arrays of \(Q\)-polynomial Shilla graphs...

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Main Authors: Alexander A. Makhnev, Ivan N. Belousov
Format: Article
Language:English
Published: Krasovskii Institute of Mathematics and Mechanics of the Ural Branch of the Russian Academy of Sciences and Ural Federal University named after the first President of Russia B.N.Yeltsin. 2021-12-01
Series:Ural Mathematical Journal
Subjects:
Online Access:https://umjuran.ru/index.php/umj/article/view/404
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author Alexander A. Makhnev
Ivan N. Belousov
author_facet Alexander A. Makhnev
Ivan N. Belousov
author_sort Alexander A. Makhnev
collection DOAJ
description A \(Q\)-polynomial Shilla graph with \(b = 5\) has intersection arrays \(\{105t,4(21t+1),16(t+1); 1,4 (t+1),84t\}\), \(t\in\{3,4,19\}\). The paper proves that distance-regular graphs with these intersection arrays do not exist. Moreover, feasible intersection arrays of \(Q\)-polynomial Shilla graphs with \(b = 6\) are found.
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publishDate 2021-12-01
publisher Krasovskii Institute of Mathematics and Mechanics of the Ural Branch of the Russian Academy of Sciences and Ural Federal University named after the first President of Russia B.N.Yeltsin.
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series Ural Mathematical Journal
spelling doaj.art-becc78a618674e87bf944b8d6599add72022-12-22T02:05:24ZengKrasovskii Institute of Mathematics and Mechanics of the Ural Branch of the Russian Academy of Sciences and Ural Federal University named after the first President of Russia B.N.Yeltsin.Ural Mathematical Journal2414-39522021-12-017210.15826/umj.2021.2.004130SHILLA GRAPHS WITH \(b=5\) AND \(b=6\)Alexander A. Makhnev0Ivan N. Belousov1Krasovskii Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences, 16 S. Kovalevskaya Str., Ekaterinburg, 620108; Ural Federal University, 19 Mira Str., Ekaterinburg, 620002Krasovskii Institute of Mathematics and Mechanics, Ural Branch of the Russian Academy of Sciences, 16 S. Kovalevskaya Str., Ekaterinburg, 620108; Ural Federal University, 19 Mira Str., Ekaterinburg, 620002A \(Q\)-polynomial Shilla graph with \(b = 5\) has intersection arrays \(\{105t,4(21t+1),16(t+1); 1,4 (t+1),84t\}\), \(t\in\{3,4,19\}\). The paper proves that distance-regular graphs with these intersection arrays do not exist. Moreover, feasible intersection arrays of \(Q\)-polynomial Shilla graphs with \(b = 6\) are found.https://umjuran.ru/index.php/umj/article/view/404shilla graph, distance-regular graph, q-polynomial graph.
spellingShingle Alexander A. Makhnev
Ivan N. Belousov
SHILLA GRAPHS WITH \(b=5\) AND \(b=6\)
Ural Mathematical Journal
shilla graph, distance-regular graph, q-polynomial graph.
title SHILLA GRAPHS WITH \(b=5\) AND \(b=6\)
title_full SHILLA GRAPHS WITH \(b=5\) AND \(b=6\)
title_fullStr SHILLA GRAPHS WITH \(b=5\) AND \(b=6\)
title_full_unstemmed SHILLA GRAPHS WITH \(b=5\) AND \(b=6\)
title_short SHILLA GRAPHS WITH \(b=5\) AND \(b=6\)
title_sort shilla graphs with b 5 and b 6
topic shilla graph, distance-regular graph, q-polynomial graph.
url https://umjuran.ru/index.php/umj/article/view/404
work_keys_str_mv AT alexanderamakhnev shillagraphswithb5andb6
AT ivannbelousov shillagraphswithb5andb6