[Settfa] Tuesday 30/11, N. Christopher Phillips

[kubis at math.cas.cz]

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 Tuesday 30th November, 10:00am 
 
  Place: IM in konírna 

 
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 Speaker:N. Christopher Phillips, University of Oregon
 Title: Incompressible Banach algebras

 Abstract  

 Let A be a Banach algebra. We say that A is incompressibleif every injective homomorphism from A to another Banach algebrais bounded below, uniformly incompressible if there is a nonzerolower bound depending only on the norm of the homomorphism, andisometrically incompressible if every contractive injectivehomomorphism from A to another Banach algebra is isometric.Incompressibility has been considered (under other names) in thepast, although without any systematic theory. For example, thealgebra of bounded operators on a Banach space, certain Calkinalgebras, and all C*-algebras are uniformly and isometricallyincompressible. The last result has led to the idea that a "C* like"L^p operator algebra should be incompressible. The disk algebra andthe algebra of bounded infinite upper triangular matrices are notincompressible.
 
We describe some of the basic theory of incompressible Banachalgebras and some of the examples. This talk will use very littlemachinery.
 

 
This is joint work with Bill Johnson and Gideon Schechtman.

 For more information see the seminar web page at 
 https://calendar.math.cas.cz/set-theory-and-analysis-actual .