|  Measure Theory | 
In General > s.a. Borel Measure;
  distance and types
  of distances; vectors [inner product].
  $ Measurable space: A set X
    with a sigma field of subsets (> see ring).
  $ Measure space: A measurable
    space and a function μ, which is (1) Positive, μ:
    \(\cal A\) → \(\mathbb R\)1 ∪
    {+∞}, where \(\cal A\) is the σ-field of subsets; (2)
    Countably additive, μ(∪i
    Ai)
    = ∑i
    μ(Ai)
    for i ∈ \(\mathbb N\);
  * Sigma-finite measure: One such that there exists
    a covering {Ai}i
    ∈ \(\mathbb N\) of X = ∪i
    Ai by finite measure subsets,
    μ(Ai) < ∞
    for all i.
  * Measurable map: A map
    f : X → Y is measurable iff the pre-image of every
    measurable set in Y is a measurable set in X; Notice that if the
    measures in question are Borel measures, all continuous maps are measurable.
Measure on a Group
  * Haar measure: A left-invariant
    regular Borel measure on a (locally connected) Lie group; It is guaranteed
    to exist (on a locally connected Lie group); It is unique on a compact group,
    and determined up to a global factor on a non-compact group.
  @ Haar measure: Creutz JMP(78) [on SU(N)];
    Sun et al ht/01 [non-existence on
      C∞(\(\mathbb R\)n, U(1))];
    Niemiec T&A(08) [generalization];
    > s.a. lie groups.
  @ On special groups: Sun et al ht/01 [on
      C∞(\(\mathbb R\)n, G)];
    > s.a. examples of lie groups; Virasoro Group.
On Rn or Integers > see Central Limit Theorem; Gamma, gaussian, Poisson Distribution.
On Other Sets > s.a. boundaries [measure on boundary
  conditions]; connection;  lie group;
  loop; posets [partially ordered measure spaces].
  * On a set of paths:
    The Wiener measure, introduced in the theory of brownian motion, amounts to
    approximating each path as being piecewise linear, performing a finite number
    of integrations over the intermediate positions and taking a limit.
  * On a set of evolutions:
    If we identify the set of dynamical evolutions with the (covariant) phase
    space, we can use the Liouville measure.
  @ Wiener measure: Stroock & Varadhan 79;
    Choquet-Bruhat et al 82, p583;
    Andersson & Driver JFA(99) [approximations];
    Jiang JSP(14) [relationship between two types of Wiener measures];
    Belokurov & Shavgulidze a1812 [polar decomposition, calculations].
  @ Other measures on paths:
    Durhuus & Jonsson mp/00;
    Betz et al mp/04 [Gibbs measures on Brownian paths];
    > s.a. loops.
  @ Sets of transformations: Niemiec T&A(06) [equicontinuous semigroups of continuous transformations of a compact Hausdorff space].
  @ Infinite-dimensional linear spaces: Gel'fand & Vilenkin 64;
    Yamasaki 85; > s.a. path integrals.
  @ Other infinite-dimensional sets:
    Ashtekar & Lewandowski JMP(95) [connections];
    Menotti & Peirano NPB(97)ht/96 [Euclidean metrics];
    Djah et al mp/04 [functional, Feynman-graph representation];
    Vershik mp/07 [Lebesgue measure];
    > s.a. Prevalence; random fields.
And Physics > s.a. probability in physics.
  * Classical vs quantum measures:
    A classical measure satisfies μ(A ⊔ B) 
    = μ(A) + μ(B) for disjoint events
    A and B; A quantum measure satisfies μ(A ⊔
    B ⊔ C) = μ(A ⊔ B)
    + μ(A ⊔ C) + μ(B ⊔
    C) − μ(A) − μ(B) −
    μ(C) for disjoint events A, B and C.
  @ For classical systems: Werner JMP(11) [dynamically defined measures and equilibrium states].
  @ On the space of mixed quantum states:
    Życzkowski & Sommers JPA(01)qp/00.
  @ (Positive) operator-valued measures: in Holevo 82;
    in Busch et al 95;
    Cassinelli et al qp/02,
    JMP(03)qp [and group action];
    Skulimowski PLA(02),
    PLA(02) [and time];
    Gazeau & Heller a1408 [POVM quantization].
  @ On projection lattices of von Neumann algebras:
    Hamhalter 03.
  @ Quantum measures: Sorkin MPLA(94)gq,
    in(97)gq/95;
    Salgado MPLA(02)gq/99;
    Zafiris JMP(06) [sheaf-theoretic representation];
    Craig et al JPA(07)qp/06 [and Bell inequality analog];
    Sorkin JPA(07)qp/06;
    Barnett et al JPA(07) [Popescu-Rohrlich boxes];
    Dowker & Ghazi-Tabatabai JPA(08)-a0712 [dynamical wave-function-collapse models];
    Surya & Wallden FP(10)-a0809 [quantum covers];
    Ghazi-Tabatabai PhD(09)-a0906 [new interpretation];
    Gudder JMP(09)-a0909 [and integration theory],
    RPMP(11)-a1005 [and coevent interpretation];
    Dowker et al JPA(10)-a1007;
    Gudder a1009-proc [and quantum computers];
    Gudder a1011 [Hilbert-space representation];
    Sorkin a1104-in;
    Gudder RPMP(12) [and integrals];
    Xie et al FP(13) [super quantum measures on finite spaces];
    Joshi et al IJQI(16)-a1308 [higher-order, no-signaling violation];
    Boës & Navascués PRD(17)-a1609 [composing decoherence functionals];
    Mozota & Sorkin IJTP(17)-a1610 [determining μ(E) experimentally];
    > s.a. integration [quantum integrals];
      random walk [quantum].
  @ Related topics: Markowich et al JFA-a0911 [Bohmian interpretation and phase-space measures].
  > Specific areas of physics:
    see multiverse; foundations
      of quantum mechanics; path integrals [including coevent formulation];
      quantum gauge theory.
Other References > s.a. functional analysis.
  @ General: Kolmogorov & Fomin 61;
    Halmos 74;
    Swartz 94 [and function spaces];
    Cohn 13 [III];
    Weaver 13 [III, and functional analysis].
  @ And probability:  Doob 94;
    Adams & Guillemin 96.
  @ Books, special emphasis: Parthasarathy 67 [probability measures];
    Chaumont & Yor 12 [problems, r CP(13)].
  @ Geometric: Federer 69;
    Klain & Rota 97.
  @ Spaces of measures: Busch LMP(98)mp [orthogonality and disjointness];
      > s.a. types of metrics.
  @ Related topics: Eckmann et al Nonlin(00)cd/99,
    cd/99-conf [porosity and dimension];
    Finster JraM(10)-a0811 [causal variational principles].
  > Online resources:
    David Fremlin's book.
 main page
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  send feedback and suggestions to bombelli at olemiss.edu – modified 16 dec 2018