Skip to main content

Part of the book series: Mathematics and Its Applications ((MAIA,volume 478))

Abstract

It is known that for (bounded) self-adjoint operators A,B on a Hilbert space H the infimum AB, with respect to the order induced by the cone of positive (semi-definite) operators, exists only when A and B are comparable, that is, AB or AB. In this paper we present a necessary and sufficient condition for that, given A,B ≥ 0, the iniimum considered in the positive cone exists.

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

Access this chapter

Chapter
USD 29.95
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
eBook
USD 39.99
Price excludes VAT (USA)
  • Available as PDF
  • Read on any device
  • Instant download
  • Own it forever
Softcover Book
USD 54.99
Price excludes VAT (USA)
  • Compact, lightweight 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

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. W.N. Anderson, Jr. and R.J. Duffin, Series and parallel addition of matrices, J. Math. Anal. Appl. 26(1969), 576–594.

    Article  MathSciNet  MATH  Google Scholar 

  2. W.N. Anderson, Jr. and M. Schreiber, The infima of two projections, Acta Sci. Math. (Szeged) 33(1972), 165–168.

    MathSciNet  MATH  Google Scholar 

  3. W.N. Anderson, Jr. and G.E. Trapp, Shorted operators II, SIAM J. Appl. Math. 28(1975), 60–71.

    Article  MathSciNet  MATH  Google Scholar 

  4. T. Ando, Lebesgue-type decomposition of positive operators, Acta Sci. Math. (Szeged), 38(1976), 253–260.

    MathSciNet  MATH  Google Scholar 

  5. —, Parametrization of minimal points of some convex sets of matrices, Acta Sci. Math. (Szeged), 57(1993), 3–10.

    MathSciNet  MATH  Google Scholar 

  6. S. Gudder, Lattice properties of quantum effects, J. Math. Phys. 37(1996), 2637–2642.

    Article  MathSciNet  MATH  Google Scholar 

  7. —, Examples, problems, and results in effect algebras, Int. J. Theor. Phys. 35(1996), 2365–2376.

    Article  MathSciNet  MATH  Google Scholar 

  8. P. Lahti and M. Maczynski, On the order structure of the set of effects in quantum mechanics, J. Math. Phys. 36(1995), 1673–1680.

    Article  MathSciNet  MATH  Google Scholar 

  9. T. Moreland and S. Gudder, Infima of Hilbert space effects, to appear in Linear Alg. Appl.

    Google Scholar 

  10. K. Nishio, Characterization of Lebesgue-type decompositon of positive operators, Acta Sci. Math. (Szeged), 42(1980), 143–152.

    MathSciNet  MATH  Google Scholar 

  11. E.L. Pekarev and Ju. L. Smul’yan, Parallel addtion and parallel subtraction of operators, Izv. Akad. Nauk SSSR, Ser. Mat. 40(1976), 366–387.

    MathSciNet  Google Scholar 

Download references

Author information

Authors and Affiliations

Authors

Editor information

Editors and Affiliations

Rights and permissions

Reprints and permissions

Copyright information

© 1999 Springer Science+Business Media Dordrecht

About this chapter

Cite this chapter

Ando, T. (1999). Problem of Infimum in the Positive Cone. In: Rassias, T.M., Srivastava, H.M. (eds) Analytic and Geometric Inequalities and Applications. Mathematics and Its Applications, vol 478. Springer, Dordrecht. https://doi.org/10.1007/978-94-011-4577-0_1

Download citation

  • DOI: https://doi.org/10.1007/978-94-011-4577-0_1

  • Publisher Name: Springer, Dordrecht

  • Print ISBN: 978-94-010-5938-1

  • Online ISBN: 978-94-011-4577-0

  • eBook Packages: Springer Book Archive

Publish with us

Policies and ethics