BANACH ALGEBRA ELEMENTS OF THIN NUMERICAL RANGE Academic Article uri icon

abstract

  • Among the elements of a complex unital Banach algebra the real subspace of hermitian elements deserves special attention. This forms the natural generalization of the set of self-adjoint elements in a C*-algebra and exhibits many of the same properties. Two equivalent definitions may be given: if W(h) , where W(h) denotes the numerical range of h (7), or if eih = 1 for all . In this paper some related subsets are introduced and studied. For 0, an element is said to be a member of if the conditionis satisfied. These may be termed the elements of thin numerical range if is small.

published proceedings

  • MATHEMATICAL PROCEEDINGS OF THE CAMBRIDGE PHILOSOPHICAL SOCIETY

author list (cited authors)

  • SMITH, R. R.

citation count

  • 6

complete list of authors

  • SMITH, RR

publication date

  • July 1979