Constructing segments of quadratic length in Spec(T_n) through segments of linear length

Constructing segments of quadratic length in $Spec(T_n)$ through segments of linear length

Kravchuk A. V.

УДК 519.1
DOI: 10.33048/semi.2024.21.061 
MSC 05C25, 05E10, 05E15


Аннотация:

A Transposition graph Tn is defined as a Cayley graph over the symmetric group $Sym_n$ generated by all transpositions. It is known that the spectrum of $T_n$ consists of integers, but it is not known exactly how these numbers are distributed. In this paper we prove that integers from the segment $[−n, n]$ lie in the spectrum of $T_n$ for any $n \ge 31$. Using this fact we also prove the main result of this paper that a segment of quadratic length with respect to $n$ lies in the spectrum of $T_n$.

Ключевые слова: Transposition graph, integral graph, spectrum