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Spectral Extremal Results with Forbidding Linear Forests

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Abstract

The Turán type extremal problems ask to maximize the number of edges over all graphs which do not contain fixed subgraphs. Similarly, their spectral counterparts ask to maximize spectral radius of all graphs which do not contain fixed subgraphs. In this paper, we determine the maximum spectral radius of all graphs without a linear forest as a subgraph and all the extremal graphs. In addition, the maximum number of edges and spectral radius of all bipartite graphs without \(k\cdot P_3\) as a subgraph are obtained and all the extremal graphs are also determined. Moreover, some relations between Turán type extremal problems and their spectral counterparts are discussed.

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References

  1. Bhattacharya, A., Friedland, S., Peled, U.N.: On the first eigenvalue of bipartite graphs. Electron. J. Combin. 15, 1–23 (2008)

    MathSciNet  MATH  Google Scholar 

  2. Bondy, J.A., Murty, U.S.R.: Graph Theory. Springer, New York (2007)

    MATH  Google Scholar 

  3. Bushaw, N., Kettle, N.: Turán numbers of multiple paths and equibipartite forests. Comb. Probab. Comput. 20, 837–853 (2011)

    Article  MATH  Google Scholar 

  4. Campos, V., Lopes, R.: A proof for a conjecture of Gorgol. Electron. Notes Discrete Math. 50, 367–372 (2015)

    Article  MATH  Google Scholar 

  5. Ellingham, M.N., Zha, X.: The spectral radius of graphs on surfaces. J. Comb. Theory Ser. B 78, 45–46 (2000)

    Article  MathSciNet  MATH  Google Scholar 

  6. Erdős, P., Gallai, T.: On maximal paths and circuits of graphs. Acta Math. Acad. Sci. Hung. 10, 337–356 (1959)

    Article  MathSciNet  MATH  Google Scholar 

  7. Favaron, O., Mahéo, M., Saclé, J.-F.: Some eigenvalue properties in graphs (conjectures of Graffiti-II). Discrete Math. 111, 197–220 (1993)

    Article  MathSciNet  MATH  Google Scholar 

  8. Hong, Y., Shu, J.-L., Fang, K.-F.: A sharp upper bound of the spectral radius of graphs. J. Comb. Theory Ser. B 81, 177–183 (2001)

    Article  MathSciNet  MATH  Google Scholar 

  9. Lidický, B., Liu, H., Palmer, C.: On the Turán number of forests. Electron. J. Comb. 20, 1–13 (2013)

    MATH  Google Scholar 

  10. Lovász, L., Pelikán, J.: On the eigenvalues of trees. Period. Math. Hung. 3, 175–182 (1973)

    Article  MathSciNet  MATH  Google Scholar 

  11. Nikiforov, V.: Some inequalities for the largest eigenvalue of a graph. Comb. Probab. Comput. 11, 179–189 (2002)

    Article  MathSciNet  MATH  Google Scholar 

  12. Nikiforov, V.: Bounds on graph eigenvalues II. Linear Algebra Appl. 427, 183–189 (2007)

    Article  MathSciNet  MATH  Google Scholar 

  13. Nikiforov, V.: A spectral condition for odd cycles in graphs. Linear Algebra Appl. 428, 1492–1498 (2008)

    Article  MathSciNet  MATH  Google Scholar 

  14. Nikiforov, V.: A spectral Erdős–Stone–Bollobás theorem. Comb. Probab. Comput. 18, 455–458 (2009)

    Article  MATH  Google Scholar 

  15. Nikiforov, V.: The maximum spectral radius of \(C_4\)-free graphs of given order and size. Linear Algebra Appl. 430, 2898–2905 (2009)

    Article  MathSciNet  MATH  Google Scholar 

  16. Nikiforov, V.: A contribution to the Zarankiewicz problem. Linear Algebra Appl. 432, 1405–1411 (2010)

    Article  MathSciNet  MATH  Google Scholar 

  17. Nikiforov, V.: The spectral radius of graphs without paths and cycles of specified length. Linear Algebra Appl. 432, 2243–2256 (2010)

    Article  MathSciNet  MATH  Google Scholar 

  18. Turán, P.: On an extremal problem in graph theory. Mat. Fiz. Lapok 48(137), 436–452 (1941)

    MathSciNet  Google Scholar 

  19. Tait, M., Tobin, J.: Three conjectures in extremal spectral graph theory. J. Comb. Theory Ser. B 126, 137–161 (2017)

    Article  MathSciNet  MATH  Google Scholar 

  20. Yuan, L.-T., Zhang, X.-D.: The Turán number of disjoint copies of paths. Discrete Math. 340, 132–139 (2017)

    Article  MathSciNet  MATH  Google Scholar 

  21. Yuan, W., Wang, B., Zhai, M.: On the spectral radii of graphs without given cycles. Electron. J. Linear Algebra 23, 599–606 (2012)

    MathSciNet  MATH  Google Scholar 

  22. Zhai, M., Wang, B.: Proof of a conjecture on the spectral radius of \(C_4\)-free graphs. Linear Algebra Appl. 437, 1641–1647 (2012)

    Article  MathSciNet  MATH  Google Scholar 

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Acknowledgements

The authors would like to thank the anonymous referee for many helpful and constructive suggestions to an earlier version of this paper, which results in an great improvement.

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Correspondence to Xiao-Dong Zhang.

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This work is supported by the Joint NSFC-ISF Research Program (jointly funded by the National Natural Science Foundation of China and the Israel Science Foundation (no. 11561141001)), the National Natural Science Foundation of China (no. 11531001), and the Weng Hongwu Research Foundation of Peking University (no. WHW201803).

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Chen, MZ., Liu, AM. & Zhang, XD. Spectral Extremal Results with Forbidding Linear Forests. Graphs and Combinatorics 35, 335–351 (2019). https://doi.org/10.1007/s00373-018-1996-3

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  • DOI: https://doi.org/10.1007/s00373-018-1996-3

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