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Article #192Set-free measure theory
From: Cameron Laird
Date: Tue, 26 Jan 1993 14:47
Date: Tue, 26 Jan 1993 14:47
32 lines
1913 bytes
1913 bytes
I propose this definition: a "set-free measure" is a triple <X, m, T> with 1. X a lattice (boolean algebra), 2. m a function defined on the members of X, and 3. T an equivalence relation on X, for which 4. m(x + y) = m(x) + m(y) - m(x.y) and 5. xTy implies m(x) = m(y). The natural model for such an object is conventional measure theory, with X a collection of Borel sets, or measurable sets, taken from an abelian group, and T translation (that is, read xTy as "x is a translate of y"). Are there any (non-trivial) others? I realize I haven't constrained the range of m (finite, includes zero, non-negative, ...), or adjoined a countable version of 4; if doing so makes the problem more interesting, then I'd want to know. Conjecture: the literature already includes a proof that there is nothing novel about "set-free measures", that is, they all have realizations as (extended) measures. Does anyone know? I write "set-free" to emphasize the historical attention directed away from the point-set flavor typical of measure theory, and toward a categorical attention to the action of the function m. -- Cameron Laird claird@Neosoft.com (claird%Neosoft.com@uunet.uu.net) +1 713 267 7966 claird@litwin.com (claird%litwin.com@uunet.uu.net) +1 713 996 8546
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arc1-ca.pugleaf.net!sparky!uunet!tcsi.com!iat.holonet.net!news.cerf.net!usc!sdd.hp.com!ux1.cso.uiuc.edu!news.cso.uiuc.edu!danShow Full Headers
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Newsgroups: sci.math.research Path: arc1-ca.pugleaf.net!sparky!uunet!tcsi.com!iat.holonet.net!news.cerf.net!usc!sdd.hp.com!ux1.cso.uiuc.edu!news.cso.uiuc.edu!dan From: claird@NeoSoft.com (Cameron Laird) Subject: Set-free measure theory Message-ID: <C1GuEp.M99@sugar.neosoft.com> Originator: dan@symcom.math.uiuc.edu Sender: Daniel Grayson <dan@math.uiuc.edu> X-Submissions-To: sci-math-research@uiuc.edu Organization: NeoSoft Communications Services -- (713) 684-5900 X-Administrivia-To: sci-math-research-request@uiuc.edu Approved: Daniel Grayson <dan@math.uiuc.edu> Date: Tue, 26 Jan 1993 14:47:10 GMT Lines: 33