|  Manifolds | 
In General
  $ Def: A topological space in which
    every point has an open neighborhood homeomorphic to an open  n-ball.
  * Properties: It is finite-dimensional,
    locally contractible, satisfies the Alexander-Lefschetz duality relationships.
  > Types of manifolds: see
    cell complex; differential
    geometry; differentiable manifolds;
    types of manifolds [combinatorial, PL, topological, etc].
  > Online resources: see the Manifold
    Atlas Project site.
Algebraic Characterization
  * Idea: The structure of a manifold
    can be recovered from the C*-algebra generated by appropriate functions (abstractly,
    in several ways, e.g., as ideals or as propagators corresponding to point sources).
  $ Gel'fand-Naimark theorem:
    A C*-algebra \({\cal A}\) with identity is isomorphic to the C*-algebra of continuous
    bounded functions on a compact Hausdorff space, the spectrum of \({\cal A}\);
    The spectrum can be constructed directly, as the set of maximal ideals, or *-homomorphisms
    \({\cal A}\) → \({\mathbb C}\).
  $ Gel'fand-Kolmogorov theorem:
    (1939) A compact Hausdorff topological space X can be canonically embedded
    into the infinite-dimensional vector space C(X)*, the dual space
    of the algebra of continuous functions C(X) as an "algebraic
    variety" specified by an infinite system of quadratic equations.
  @ General references: Fell & Doran 88;
    Khudaverdian & Voronov AIP(07)-a0709 [generalization of Gel'fand-Kolmogorov];
    Izzo AM(11).
  @ Related topics: Connes a0810 [spectral triples];
  > s.a. non-commutative geometry.
Additional Structures of Manifolds > s.a. fiber bundles.
* Possibilities: Different levels of structure are manifold,
  triangulable manifold, PL manifold, differentiable manifold; For a while, the first two or three
  of these structures were conjectured to be equivalent, but now this has been shown to be false.
* Multiplication structure:
  A map *: M × M → M.
* Comultiplication: A mapping F: C(M) → C(M)
  ⊗ C(M) on the algebra of functions on M.
  * Relationship: If M has a multiplication,
  then it gets a (diagonal) comultiplication Δ defined
  by f \(\mapsto\) Δ(f): Δf(x,y)
  = F(x * y).
@ References: Kankaanrinta T&A(05)
[G-manifolds and Riemannian metrics].
Constructions and Operations on Manifolds
  > s.a. category; embeddings;
  foliations; tensor [product].
  $ Direct product:
    Given two manifolds Xn and
    Y p, their direct product
    is Zn+p
    = Xn × Y p as
    a set, with the product topology and the product
    charts: UZ
    = UX × UY,
    φZ(x,y) =
    (φX(x),
    φY(y)).
  $ Submanifold: N is
    a submanifold of M if it is a topological subspace of M
    and the inclusion map is an embedding (if it is an immersion we have an
    immersed submanifold).
  $ Integral submanifold:
    A submanifold N ⊂ M such that for all p in N,
    f*(TpN)
    = Sp, with f : N → M the embedding map.
  $ Connected sum: In sloppy
    notation, X # Y:= (X \
    Dn) ∪ (Y \
    Dn), where n is the dimension of X and Y;
    It is associative and commutative, and has Sn as
    identity; Examples: X # \(\mathbb R\)n
    = X \ {p};
    > s.a. laplacian; 3D manifolds.
  @ Submanifolds: Carter JGP(92) [outer curvature];
    Giachetta et al mp/06 [Lagrangian and Hamiltonian dynamics].
Superspace, Supermanifolds > s.a. complex structures;
  Gegenbauer, Hermite and
  Jack Polynomials; geometric quantization.
  * Idea: A manifold with the
    bundle-like addition of a vector space of Grassmann numbers at each point.
  * Q-manifolds: A Q-manifold
    is a supermanifold equipped with an odd vector field satisfying {Q, åQ} = 0.
  @ General references: Rabin & Crane CMP(86);
    Bagger pr(87);
    Nelson IJMPA(88);
    Bandyopadhyay & Ghosh IJMPA(89);
    De Bie & Sommen AP(07)a0707 [Clifford analysis approach];
    Santi a0905 [homogeneous supermanifolds];
    Hübsch a0906 [size and algebro-geometric structure];
    Cattaneo & Schätz RVMP(11)-a1011-ln;
    Voronov JGP(17)-a1409 [extending the category];
    Castellani et al NPB(15)-a1503,
    NPB(15)-a1507 [geometry, Hodge dual].
  @ Texts, reviews: Hermann 77;
    Chow IJTP(78);
    DeWitt 92;
    Howe & Hartwell CQG(95);
    Howe & Rogers 01; Rogers 07;
    Sardanashvily a0910-ln;
    Fioresi & Lledó 15;
    Hélein a2006-ln [intro].
  @ Quantum superspace:
    Brink & Schwarz PLB(81).
  @ With metric structure: 
    Sardanashvily IJGMP(08) [supermetrics];
    Asorey & Lavrov JMP(09) [symplectic and metric structures];
    Dumitrescu et al JHEP(12)-a1205 [curved];
    > s.a. killing tensors.
  @ Integration: Gates ht/97-conf;
    Cartier et al mp/02-in;
    De Bie & Sommen JPA(07)-a0705  [and spherical harmonics];
    > s.a. grassmann structures.
  @ Fedosov supermanifolds: Geyer & Lavrov IJMPA(04)ht/03 [symplectic];
    Lavrov & Radchenko TMP(06);
    Asorey et al a0809-conf [and Riemannian];
    Monterde et al JGP(09).
  @ Q-manifolds: Schwarz LMP(00)ht [and gauge theory];
    > s.a. characteristic classes.
  @ Physics: Kochan JGP(04)m.DG/03 [supergeometry, electromagnetism and gravity];
    Cirilo-Lombardo EPJC(12)-a1205 [geometrical properties];
    Hack et al CMP(16)-a1501 [and locally covariant quantum field theory];
    Nicolis a1606-conf
      [and the partition function, fluctuations of a non-relativistic particle];
    > s.a. Double Field Theory; FLRW
      spacetimes; scalar fields [on supersphere].
  @ Related topics: Bruzzo & Pestov JGP(99);
    Philbin ht/03-wd [topology];
    Constantinescu JPA(05)ht/04,
    MPLA(05)ht/04 [inner product, Hilbert-Krein structure];
    Desrosiers et al m.CO/04 [symmetric functions];
    Bruce ArchM-a1401 [curve and jet of a curve];
    Randall a1412-th [closed forms in superspace];
    Bruce & Ibarguengoytia a1806 [generalization, \(\mathbb{Z}_2^n\)-manifolds];
    Klinker CMP(05)-a2001 [supergeometry and supersymmetry];
    Bruce & Grabowski a2005 [odd connections];
    > s.a. brownian motion; spherical functions.
  > Other generalizations:
    see differential geometry [including fuzzy]; differentiable
    manifolds [exotic structures]; types of manifolds [including pseudomanifolds];
    Wilson Loop.
 main page
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  send feedback and suggestions to bombelli at olemiss.edu – modified 4 jun 2020