z-logo
Premium
On a Topological Property of certain Calkin Algebras
Author(s) -
Meyer Michael J.
Publication year - 1992
Publication title -
bulletin of the london mathematical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.396
H-Index - 48
eISSN - 1469-2120
pISSN - 0024-6093
DOI - 10.1112/blms/24.6.591
Subject(s) - mathematics , bounded function , norm (philosophy) , quotient , bounded operator , linear operators , operator algebra , compact operator , ideal (ethics) , combinatorics , subspace topology , algebra over a field , discrete mathematics , pure mathematics , mathematical analysis , extension (predicate logic) , philosophy , epistemology , political science , computer science , law , programming language
Let X = 1 p , 1 ⩽ p < ∞, or X = c 0 , B ( X ) be the algebra of all bounded linear operators on X , H ( X ) be the ideal of compact operators in B ( X ), and C ( X ) = B ( X )/ H ( X ) be the Calkin algebra on X . For T ε B ( X ), let ∥ T ∥ c = dist( T , H ( X )) be the essential norm of T that is the norm of T + H ( X ) in C ( X ). It is shown that for any operator T ε B ( X ) and any number 0 < t < 1, there exists a closed infinite dimensional subspace Z Z ⊆ X such that ∥ Tx∥ ⩾ t ∥ T ∥ c , for all x ε Z . As a consequence, it is shown that every (not necessarily complete) submultiplicative norm on the Calkin algebra C ( X ) is equivalent to the quotient norm ∥ ∥ c on C ( X ).

This content is not available in your region!

Continue researching here.

Having issues? You can contact us here
Accelerating Research

Address

John Eccles House
Robert Robinson Avenue,
Oxford Science Park, Oxford
OX4 4GP, United Kingdom