The conjugate of a product of linear relations

Jacob J. Jaftha

Commentationes Mathematicae Universitatis Carolinae (2006)

  • Volume: 47, Issue: 2, page 265-273
  • ISSN: 0010-2628

Abstract

top
Let X , Y and Z be normed linear spaces with T ( X Y ) and S ( Y Z ) linear relations, i.e. setvalued maps. We seek necessary and sufficient conditions that would ensure that ( S T ) ' = T ' S ' . First, we cast the concepts of relative boundedness and co-continuity in the set valued case and establish a duality. This duality turns out to be similar to the one that exists for densely defined linear operators and is then used to establish the necessary and sufficient conditions. These conditions are similar to those for the single valued case. In the process, the well known characterisation of relativeboundedness for closed linear operators by Sz.-Nagy is extended to the multivalued linear maps and we compare our results to other known necessary and sufficient conditions.

How to cite

top

Jaftha, Jacob J.. "The conjugate of a product of linear relations." Commentationes Mathematicae Universitatis Carolinae 47.2 (2006): 265-273. <http://eudml.org/doc/249842>.

@article{Jaftha2006,
abstract = {Let $X$, $Y$ and $Z$ be normed linear spaces with $T(X\rightarrow Y)$ and $S(Y\rightarrow Z)$ linear relations, i.e. setvalued maps. We seek necessary and sufficient conditions that would ensure that $(ST)^\{\prime \}=T^\{\prime \}S^\{\prime \}$. First, we cast the concepts of relative boundedness and co-continuity in the set valued case and establish a duality. This duality turns out to be similar to the one that exists for densely defined linear operators and is then used to establish the necessary and sufficient conditions. These conditions are similar to those for the single valued case. In the process, the well known characterisation of relativeboundedness for closed linear operators by Sz.-Nagy is extended to the multivalued linear maps and we compare our results to other known necessary and sufficient conditions.},
author = {Jaftha, Jacob J.},
journal = {Commentationes Mathematicae Universitatis Carolinae},
keywords = {linear relations; conjugates; linear operators; linear relation; conjugate; linear operator},
language = {eng},
number = {2},
pages = {265-273},
publisher = {Charles University in Prague, Faculty of Mathematics and Physics},
title = {The conjugate of a product of linear relations},
url = {http://eudml.org/doc/249842},
volume = {47},
year = {2006},
}

TY - JOUR
AU - Jaftha, Jacob J.
TI - The conjugate of a product of linear relations
JO - Commentationes Mathematicae Universitatis Carolinae
PY - 2006
PB - Charles University in Prague, Faculty of Mathematics and Physics
VL - 47
IS - 2
SP - 265
EP - 273
AB - Let $X$, $Y$ and $Z$ be normed linear spaces with $T(X\rightarrow Y)$ and $S(Y\rightarrow Z)$ linear relations, i.e. setvalued maps. We seek necessary and sufficient conditions that would ensure that $(ST)^{\prime }=T^{\prime }S^{\prime }$. First, we cast the concepts of relative boundedness and co-continuity in the set valued case and establish a duality. This duality turns out to be similar to the one that exists for densely defined linear operators and is then used to establish the necessary and sufficient conditions. These conditions are similar to those for the single valued case. In the process, the well known characterisation of relativeboundedness for closed linear operators by Sz.-Nagy is extended to the multivalued linear maps and we compare our results to other known necessary and sufficient conditions.
LA - eng
KW - linear relations; conjugates; linear operators; linear relation; conjugate; linear operator
UR - http://eudml.org/doc/249842
ER -

References

top
  1. van Casteren J.A.W., Goldberg S., The conjugate of a product of operators, Studia Math. 38 (1970), 125-130. (1970) MR0275192
  2. Cross R.W., Multivalued Linear Operators, Marcel Dekker, New York, 1998. Zbl0911.47002MR1631548
  3. Förster K.-H., Liebetrau E.-O., On semi-Fredholm operators and the conjugate of a product of operators, Studia Math. 59 (1976/77), 301-306. (1976/77) MR0435883
  4. Förster K.-H., Relativ co-stetige Operatoren in normierten Räumen, Arch. Math. 25 (1974), 639-645. (1974) MR0397459
  5. Kaashoek M.A., Closed linear operators on Banach spaces, Ph.D. Thesis, Univ. Leiden, 1964. Zbl0138.07502MR0185451
  6. Kascic M.J., Polynomials in linear relations, Pacific J. Math. 24 (1968), 291-295. (1968) Zbl0155.19004MR0222670
  7. Kato T., Perturbation Theory for Linear Operators, Grundlehren, vol. 132, Springer, Berlin, 1966. Zbl0836.47009
  8. Sz.-Nagy B., Perturbations des transformations linéaires fermées, Acta Sci. Math. Szeged 14 (1951), 125-137. (1951) Zbl0045.21601MR0047254

NotesEmbed ?

top

You must be logged in to post comments.

To embed these notes on your page include the following JavaScript code on your page where you want the notes to appear.

Only the controls for the widget will be shown in your chosen language. Notes will be shown in their authored language.

Tells the widget how many notes to show per page. You can cycle through additional notes using the next and previous controls.

    
                

Note: Best practice suggests putting the JavaScript code just before the closing </body> tag.