The uniqueness of Haar measure and set theory
Colloquium Mathematicum, Tome 74 (1997) no. 1, pp. 109-121
Cet article a éte moissonné depuis la source Institute of Mathematics Polish Academy of Sciences
Let G be a group of homeomorphisms of a nondiscrete, locally compact, σ-compact topological space X and suppose that a Haar measure on X exists: a regular Borel measure μ, positive on nonempty open sets, finite on compact sets and invariant under the homeomorphisms from G. Under some mild assumptions on G and X we prove that the measure completion of μ is the unique, up to a constant factor, nonzero, σ-finite, G-invariant measure defined on its domain iff μ is ergodic and the G-orbits of all points of X are uncountable. In particular, this is true if either G is a locally compact, σ-compact topological group acting continuously on X, or the space X is uniform and nonseparable, and G consists of uniformly equicontinuous unimorphisms of X.
Keywords:
real-valued measurable cardinal, invariant measure, Haar measure, locally compact space
Affiliations des auteurs :
Piotr Zakrzewski 1
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author = {Piotr Zakrzewski},
title = {The uniqueness of {Haar} measure and set theory},
journal = {Colloquium Mathematicum},
pages = {109--121},
year = {1997},
volume = {74},
number = {1},
doi = {10.4064/cm-74-1-109-121},
language = {en},
url = {http://geodesic.mathdoc.fr/articles/10.4064/cm-74-1-109-121/}
}
Piotr Zakrzewski. The uniqueness of Haar measure and set theory. Colloquium Mathematicum, Tome 74 (1997) no. 1, pp. 109-121. doi: 10.4064/cm-74-1-109-121
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