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Journal of Mathematical Sciences

, Volume 182, Issue 2, pp 193–199 | Cite as

Some further bounds for the Q-index of nested split graphs

  • M. AnđelićEmail author
  • C. M. da Fonseca
  • S. K. Simić
  • D. V. Tošić
Article

Abstract

The Q-index of a simple graph is the largest eigenvalue of its signless Laplacian, or Q-matrix. In our previous paper [1] we gave three lower and three upper bounds for the Q-index of nested split graphs, also known as threshold graphs. In this paper, we give another two upper bounds, which are expressed as solutions of cubic equations (in contrast to quadratics from [1]). Some computational results are also included.

Keywords

Spectral Theory Large Eigenvalue Simple Graph Eigenvalue Equation Computational Data 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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References

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Copyright information

© Springer Science+Business Media, Inc. 2012

Authors and Affiliations

  • M. Anđelić
    • 1
    Email author
  • C. M. da Fonseca
    • 2
  • S. K. Simić
    • 3
  • D. V. Tošić
    • 4
  1. 1.Department of MathematicsUniversity of AveiroAveiroPortugal
  2. 2.Department of MathematicsUniversity of CoimbraCoimbraPortugal
  3. 3.Mathematical Institute SANUBelgradeSerbia
  4. 4.School of Electrical EngineeringUniversity of BelgradeBelgradeSerbia

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