no. 12
Functional analysis
Toral and spherical Aluthge transforms of 2-variable weighted shifts
[Transformations d'Aluthge torales et sphériques de shifts pondérés à deux variables]

Présenté par : Gilles Pisier

Curto, Raúl E.1 ; Yoon, Jasang2
1 Department of Mathematics, The University of Iowa, Iowa City, IA 52242, USA
2 School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, TX 78539, USA
Comptes Rendus. Mathématique, Tome 354 (2016) no. 12, pp. 1200-1204.

Nous introduisons deux notions naturelles des transformations d'Aluthge (torales et sphériques) pour les shifts pondérés à deux variables et nous étudions leurs propriétés. Ensuite, nous étudions la classe de shifts pondérés à deux variables sphériques et quasi-normaux, qui sont les points fixes pour la transformation d'Aluthge sphérique. Enfin, nous discutons brièvement la relation entre les shifts pondérés à deux variables qui sont sphériquement quasinormaux et ceux qui sont sphériquement isométriques.

We introduce two natural notions of Aluthge transforms (toral and spherical) for 2-variable weighted shifts and study their basic properties. Next, we study the class of spherically quasinormal 2-variable weighted shifts, which are the fixed points for the spherical Aluthge transform. Finally, we briefly discuss the relation between spherically quasinormal and spherically isometric 2-variable weighted shifts.

Reçu le :
Accepté le :
Publié le :
DOI : 10.1016/j.crma.2016.10.005
Curto, Raúl E. 1 ; Yoon, Jasang 2

1 Department of Mathematics, The University of Iowa, Iowa City, IA 52242, USA
2 School of Mathematical and Statistical Sciences, The University of Texas Rio Grande Valley, Edinburg, TX 78539, USA 
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Curto, Raúl E.; Yoon, Jasang. Toral and spherical Aluthge transforms of 2-variable weighted shifts. Comptes Rendus. Mathématique, Tome 354 (2016) no. 12, pp. 1200-1204. doi : 10.1016/j.crma.2016.10.005. http://www.numdam.org/articles/10.1016/j.crma.2016.10.005/

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☆ The first author of this paper was partially supported by NSF Grant DMS-1302666.