Naslov
A treatment of the Cauchy-Schwarz inequality in C*-modules

Autori
Arambašić, Ljiljana ; Bakić, Damir ; Moslehian, Sal Mohammad

Izvornik
Journal of mathematical analysis and applications (0022-247X) 381 (2011), 2; 546-556

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
C*-algebra ; semi-inner product C*-module ; Cauchy-Schwarz inequality ; Gram matrix

Sažetak
We study the Cauchy-Schwarz and some related inequalities in a semi-inner product module over a C*-algebra A. The key idea is to consider a semi-inner product A-module as a semi-inner product A-module with respect to another semi-inner product. In this way, we improve some inequalities such as the Ostrowski inequality and an inequality related to the Gram matrix. The induced semi-inner products are also related to the the notion of covariance and variance. Furthermore, we obtain a sequence of nested inequalities that emerges from the Cauchy-Schwarz inequality. As a consequence, we derive some interesting operator-theoretical corollaries. In particular, we show that the sequence arising from our construction, when applied to a positive invertible element of a C*-algebra, converges to its inverse.

Izvorni jezik
Engleski

Znanstvena područja
Matematika

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