The Lebesgue Integral

  • Edwin Hewitt
  • Karl Stromberg


Integration from one point of view is an averaging process for functions, and it is in this spirit that we will introduce and discuss integration. In applying an averaging process to a class \({\mathcal{F}}\) real- or complex-valued functions, a number I(f) is assigned to each \(f \in {\mathcal{F}}\). If I(f) is to be an average, then it should certainly satisfy the conditions
$$\matrix{{I(f + g) = I(f) + I(g),} \cr {I(\alpha f) = \alpha I(f)} \cr }$$
for f, \(g \in {\mathcal{F}}\) and α ∈R. A less essential but often desirable property for I is that I(f) ≧ 0 if f ≧ 0. In some cases these three properties suffice to identify the averaging process completely.


Posite Radon Prefix Summing 


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Copyright information

© Springer-Verlag Berlin · Heidelberg 1965

Authors and Affiliations

  • Edwin Hewitt
    • 1
  • Karl Stromberg
    • 2
  1. 1.The University of WashingtonUSA
  2. 2.The University of OregonUSA

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