Turkish Journal of Mathematics
Abstract
Let R be a ring with unity. The nilpotent graph of R, denoted by \Gamma_N(R), is a graph with vertex set Z_N(R)^* = {0 \neq x \in R \mid xy \in N(R) for some 0 \neq y \in R}; and two distinct vertices x and y are adjacent if and only if xy \in N(R), where N(R) is the set of all nilpotent elements of R. Recently, it has been proved that if R is a left Artinian ring, then diam(\Gamma_N(R)) \leq 3. In this paper, we present a new proof for the above result, where R is a finite ring. We study the diameter and the girth of matrix algebras. We prove that if F is a field and n \geq 3, then diam(\Gamma_N(M_n(F))) = 2. Also, we determine diam (\Gamma_N (M_2(F))) and classify all finite rings whose nilpotent graphs have diameter at most 3. Finally, we determine the girth of the nilpotent graph of matrix algebras.
DOI
10.3906/mat-1112-35
Keywords
Nilpotent graph, diameter, girth
First Page
553
Last Page
559
Recommended Citation
NIKMEHR, M. J, & Khojasteh, S (2013). On the nilpotent graph of a ring. Turkish Journal of Mathematics 37 (4): 553-559. https://doi.org/10.3906/mat-1112-35