Skip to main content

Some Rational Inequalities Inspired by Rahman’s Research

  • Chapter
  • First Online:
Progress in Approximation Theory and Applicable Complex Analysis

Part of the book series: Springer Optimization and Its Applications ((SOIA,volume 117))

  • 825 Accesses

Abstract

This paper describes three instances of our research activity in rational inequalities inspired by Professor Rahman’s research. The results include Bernstein-type inequalities for rational functions with prescribed poles, comparison inequalities for rational functions, and integral inequalities with prescribed poles and prescribed zeros.

This is a preview of subscription content, log in via an institution to check access.

Access this chapter

eBook
USD 16.99
Price excludes VAT (USA)
  • Available as EPUB and PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 129.99
Price excludes VAT (USA)
  • Compact, lightweight edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info
Hardcover Book
USD 129.99
Price excludes VAT (USA)
  • Durable hardcover edition
  • Dispatched in 3 to 5 business days
  • Free shipping worldwide - see info

Tax calculation will be finalised at checkout

Purchases are for personal use only

Institutional subscriptions

Notes

  1. 1.

    By “right formulation” we mean in the sense that when taking modulus inside the integration, the equality could be attained for some special cases - not every integral formula allows such sharp estimation.

References

  1. Aziz, A.: Inequalities for the polar derivative of a polynomial. J. Approx. Theory 55, 183–193 (1988)

    Article  MathSciNet  MATH  Google Scholar 

  2. Aziz, A., Mohammad, Q.G.: Simple proof of a theorem of Erdos and Lax. Proc. Am. Math. Soc. 80, 119–122 (1980)

    MathSciNet  MATH  Google Scholar 

  3. Aziz, A., Shah, W.M.: Some refinements of bernstein inequalities for rational functions. Glasnik Matematicki 32, 29–37 (1997)

    MathSciNet  MATH  Google Scholar 

  4. Aziz, A., Shah, W.M.: Inequalities for the polar derivative of a polynomial. Indian J. Pure Appl. Math. 29, 163–173 (1998)

    MathSciNet  MATH  Google Scholar 

  5. Baranov, A., Zarouf, R.: A model space approach to some classical inequalities for rational functions. J. Math. Anal. Appl. 418, 121–141 (2014)

    Article  MathSciNet  MATH  Google Scholar 

  6. Bonsall, F.F., Marden, M.: Critical points of rational functions with self-inversive polynomial factors. Proc. Am. Math. Soc. 5, 111–114 (1954)

    Article  MathSciNet  MATH  Google Scholar 

  7. Borwein, P., Erdélyi, T.: Sharp extensions of Bernstein inequalities to rational functions. Mathematika 43, 413–423 (1996)

    Article  MathSciNet  Google Scholar 

  8. Bruijn, N.G.: Inequalities Concerning polynomials in the complex domain. Nederl. Akad. Wetensch. Proc. 50, 1265–1272 (1947)

    MathSciNet  MATH  Google Scholar 

  9. Duffin, R.J., Schaeffer, A.C.: A refinement of an inequality of the brothers Markoff. Trans. Am. Math. Soc. 50, 517–528 (1941)

    Article  MathSciNet  MATH  Google Scholar 

  10. Frappier, C., Rahman, Q.I., Ruscheweyh, St.: New inequalities for polynomials. Trans. Am. Math. Soc. 288, 69–99 (1985)

    Article  MathSciNet  MATH  Google Scholar 

  11. Frappier, C., Rahman, Q.I., Ruscheweyh, St.: On polynomials with a prescribed zero. Constr. Approx. 2, 171–177 (1986)

    Article  MathSciNet  MATH  Google Scholar 

  12. Gardner, R., Govil, N.K.: Inequalities concerning the L p-norm of a polynomial and its derivatives. J. Math. Anal. Appl. 179, 208–213 (1993)

    Article  MathSciNet  MATH  Google Scholar 

  13. Giroux, A., Rahman, Q.I.: Inequalities for polynomials with a prescribed zero. Trans. Am. Math. Soc. 193, 67–98 (1974)

    Article  MathSciNet  MATH  Google Scholar 

  14. Govil, N.K., Mohapatra, R.N.: Markov and Bernstein type inequalities for polynomials. Inequal. Appl. 3, 349–387 (1999)

    MathSciNet  MATH  Google Scholar 

  15. Govil, N.K., Rahman, Q.I.: Functions of exponential type not vanishing in a half-plane and related polynomials. Trans. Am. Math. Soc. 137, 501–517 (1969)

    Article  MathSciNet  MATH  Google Scholar 

  16. Jones, R., Li, X., Mohapatra, R.N., Rodriguez, R.S.: On the Bernstein inequality for rational functions with a prescribed zero. J. Approx. Theory 95, 476–496 (1998)

    Article  MathSciNet  MATH  Google Scholar 

  17. Lax, P.D.: Proof of a conjecture of P. Erdös on the derivative of a polynomial. Bull. Am. Math. Soc. 50, 509–513 (1944)

    Article  MATH  Google Scholar 

  18. Li, X.: Integral formulas and inequalities for rational functions. J. Math. Anal. Appl. 211, 386–394 (1997)

    Article  MathSciNet  MATH  Google Scholar 

  19. Li, X.: A comparison inequality for rational functions. Proc. Am. Math. Soc. 139, 1659–1665 (2011)

    Article  MathSciNet  MATH  Google Scholar 

  20. Li, X., Mohapatra, R.N., Rodriguez, R.S.: Bernstein-type inequalities for rational functions with prescribed poles. J. Lond. Math. Soc. 51, 523–531 (1995)

    Article  MathSciNet  MATH  Google Scholar 

  21. Liman, A., Mohapatra, R.N., Shah, W.M.: Inequalities for the polar derivative of a polynomial. Compl. Anal. oper. Theory 6, 1199–1209 (2012)

    Article  MATH  Google Scholar 

  22. Malik, M.A.: On the derivative of a polynomial. J. Lond. Math. Soc. 1, 57–60 (1968)

    MATH  Google Scholar 

  23. Malik, M.A., Vong, M.C.: Inequalities concerning the derivatives of polynomials. Rendiconti Del Circolo Matematico Di Palermo Serie II 34, 422–426 (1985)

    Article  MathSciNet  MATH  Google Scholar 

  24. Marden, M.: The Geometry of the Zeros of a Polynomial in a Complex Variable. Mathematical Surveys, vol. 3. American Mathematical Society, Providence, RI (1949)

    Google Scholar 

  25. Mohapatra, R.N., O’Hara, P.J., Rodriguez, R.S.: Simple proofs of Bernstein-type inequalities. Proc. Am. Math. Soc. 102, 629–632 (1988)

    Article  MathSciNet  MATH  Google Scholar 

  26. Olivier, P.E., Watt, A.O.: Polynomials with a prescribed zero and the Bernstein’s inequality. Can. J. Math. 45, 627–637 (1993)

    Article  MathSciNet  MATH  Google Scholar 

  27. Polya, G., Szego, G.: Problems and Theorem in Analysis I. Springer, Berlin, New York (1978)

    MATH  Google Scholar 

  28. Rahman, Q.I.: Application of Functional Analysis to Extremal Problems for Polynomials. Presses University, Montreal (1967)

    Google Scholar 

  29. Rahman, Q.I.: Functions of exponential type. Trans. Amer. Math. Soc. 137, 295–309 (1969)

    Article  MathSciNet  MATH  Google Scholar 

  30. Rahman, Q.I., Stenger, F.: An extremal problem for polynomials with a prescribed zero. Proc. Am. Math. Soc. 43, 84–90 (1974)

    Article  MathSciNet  MATH  Google Scholar 

  31. Rahman, Q.I., Schmeisser, G.: Analytic Theory of Polynomials. Oxford University Press, Oxford (2002)

    MATH  Google Scholar 

  32. Zygmund, A.: Trignometric Series. Cambridge University Press, New York (1959)

    Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Ram Mohapatra .

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 2017 Springer International Publishing AG

About this chapter

Cite this chapter

Li, X., Mohapatra, R., Ranasinghe, R. (2017). Some Rational Inequalities Inspired by Rahman’s Research. In: Govil, N., Mohapatra, R., Qazi, M., Schmeisser, G. (eds) Progress in Approximation Theory and Applicable Complex Analysis. Springer Optimization and Its Applications, vol 117. Springer, Cham. https://doi.org/10.1007/978-3-319-49242-1_6

Download citation

Publish with us

Policies and ethics