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JOURNALS // Sibirskii Matematicheskii Zhurnal // Archive

Sibirsk. Mat. Zh., 2014 Volume 55, Number 1, Pages 17–24 (Mi smj2509)

This article is cited in 4 papers

Combinatorial structure of faces in triangulated $3$-polytopes with minimum degree $4$

O. V. Borodinab, A. O. Ivanovac

a Novosibirsk State University, Novosibirsk, Russia
b Sobolev Institute of Mathematics, Novosibirsk, Russia
c Ammosov North-Eastern Federal University, Yakutsk, Sakha Republic (Yakutia)

Abstract: In 1940, Lebesgue proved that every $3$-polytope with minimum degree at least $4$ contains a $3$-face for which the set of degrees of its vertices is majorized by one of the entries: $(4,4,\infty)$, $(4,5,19)$, $(4,6,11)$, $(4,7,9)$, $(5,5,9)$, and $(5,6,7)$. This description was strengthened by Borodin (2002) to $(4,4,\infty)$, $(4,5,17)$, $(4,6,11)$, $(4,7,8)$, $(5,5,8)$, and $(5,6,6)$.
For triangulations with minimum degree at least $4$, Jendrol' (1999) gave a description of faces: $(4,4,\infty)$, $(4,5,13)$, $(4,6,17)$, $(4,7,8)$, $(5,5,7)$, and $(5,6,6)$.
We obtain the following description of faces in plane triangulations (in particular, for triangulated $3$-polytopes) with minimum degree at least $4$ in which all parameters are best possible and are attained independently of the others: $(4,4,\infty)$, $(4,5,11)$, $(4,6,10)$, $(4,7,7)$, $(5,5,7)$, and $(5,6,6)$.
In particular, we disprove a conjecture by Jendrol' (1999) on the combinatorial structure of faces in triangulated $3$-polytopes.

Keywords: plane map, plane graph, $3$-polytope, structural properties, weight.

UDC: 519.17

Received: 30.04.2013


 English version:
Siberian Mathematical Journal, 2014, 55:1, 12–18

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© Steklov Math. Inst. of RAS, 2024