Abstract
Let μ be a σ-finite measure in the (non-empty) point set X. As well-known, any finite linear combination of characteristic functions of measurable subsets of X is called a μ-step function. It is not difficult to see that for any 0 ≤ f ∈ L ∞ (X, μ) there exists a sequence (s n : n = 1, 2,…) of μ-step functions such that 0 ≤ s n ↑ f holds uniformly. A similar result holds in an Archimedean Riesz space possessing a strong unit. This result, due to H.Freudenthal (1936), is known as Freudenthal’s spectral theorem. Some preliminary theorems about projection bands will be useful. Recall that the band B in the Archimedean Riesz space E is called a projection band if E = B ⊕Bd (see section 11). In this case Bd is likewise a projection band (we have B = Bdd because E is Archimedean, so E = Bd ⊕ Bdd). As in Theorem 11.4, the band projection on the projection band B is sometimes denoted by P B . It is obvious that\( {P_{{B^d}}} = I - {P_B} \),where I is the identity operator in E (i.e., I f = f for each f ∈ E, and so\( {P_{{B^d}}}f = f - {P_B}f \)). The following holds now.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 1997 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Zaanen, A.C. (1997). Freudenthal’s Spectral Theorem. In: Introduction to Operator Theory in Riesz Spaces. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-642-60637-3_17
Download citation
DOI: https://doi.org/10.1007/978-3-642-60637-3_17
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-642-64487-0
Online ISBN: 978-3-642-60637-3
eBook Packages: Springer Book Archive