On graphs with minimal distance signless Laplacian energy

Abstract

For a simple connected graph G of order n having distance signless Laplacian eigenvalues ρ1Q≥ρ2Q≥⋯≥ρnQ\rho _1^Q \ge \rho _2^Q \ge \cdots \ge \rho _n^Q, the distance signless Laplacian energy DSLE(G) is defined as DSLE(G)=∑i=1n|ρiQ-2W(G)n|DSLE\left( G \right) = \sum\nolimits_{i = 1}^n {\left| {\rho _i^Q - {{2W\left( G \right)} \over n}} \right|} where W(G) is the Weiner index of G. We show that the complete split graph has the minimum distance signless Laplacian energy among all connected graphs with given independence number. Further, we prove that the graph Kk ∨ ( Kt∪ Kn−k−t),1≤t≤⌊n-k2⌋1 \le t \le \left\lfloor {{{n - k} \over 2}} \right\rfloor has the minimum distance signless Laplacian energy among all connected graphs with vertex connectivity k.

Keywords

• distance signless laplacian matrix
• independence number
• vertex connectivity
• extremal graphs
• 05c12
• 05c50
• 15a18