Note on Hamiltonian Graphs in Abelian 2-Groups


Download PDF

Authors: K. TABAK

DOI: 10.46793/KgJMat2503.401T

Abstract:

We analyze a graph G whose vertices are subgroups of 2k isomorphic to 2 × 2. Two vertices are joined if their respective subgroups have nontrivial intersection. We prove that such a graph is 6(2k2 1)-regular. If a graph is regular, a classical theorem by Ore claims that a graph is Hamiltonian if the degree of any vertex is at least one half of the number of vertices. Using Ore’s theorem, we show that G is Hamiltonian for k ∈{3, 4}. Ore’s theorem cannot be applied when k 5. Nevertheless, we manage to construct a Hamiltonian cycle for k = 5. Our construction uses orbits of one 24 group under an action of an automorphism of order 31. It is highly likely that this approach could be generalized for k > 5.



Keywords:

Hamiltonian graph, graph, elementary Abelian group, subgroup, group ring.



References:

[1]   A. Abdollahi, S. Akbari and H. R. Maimani, Non-commuting graph of a group, J. Algebra 298(2) (2006), 468–492. https://doi:10.1016/j.jalgebra.2006.02.015

[2]   D. F. Anderson and P. S. Livingston, The zero divisor graph of a commutative ring, J. Algebra 217(2) (1999), 434–447. https://doi.org/10.1006/jabr.1998.7840

[3]   P. Balakrishnan, M. Sattanathan and R. Kala, The center graph of a group, South Asian J. Mathematics 1 (2011), 21–28.

[4]   A. Abdollahi and A. M. Hassanabadi, Noncyclic graph of a group, Comm. Algebra 35(7) (2007), 2057–2081. https://doi.org/10.1080/00927870701302081

[5]   B. Bollobás, Modern Graph Theory, Springer-Verlag, New York, 1998.