How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
Hodge decomposition and polarization of a point
Example
Assume AC. The one-point space is a compact Kähler manifold of complex dimension zero in the sense of Compact Kähler and rational Hodge polarization conventions. Its rational cohomology is with the single Hodge type , all higher cohomology vanishes, and is a rational polarization. The hard-Lefschetz map in degree zero is the identity.
Facts & Assumptions
Given: The Axiom of Choice and the one-point space with the dimension-zero conventions of Compact Kähler and rational Hodge polarization conventions.
For a complex manifold is a discrete space, compactness makes it a finite set of points, there are no tangent vectors and no forms of positive degree, , and and all Laplacians are zero, with the Hodge star the identity on degree zero and the counting measure; the same item defines rational pure Hodge structures, the Weil operator, polarizations (nondegenerate -bilinear with , unless , and positive definite Hermitian) and the Tate shift (Compact Kähler and rational Hodge polarization conventions).
For a compact Kähler manifold , every de Rham class has a unique smooth harmonic representative and with , where is the set of classes with a -closed smooth representative of type (Compact Kähler Hodge decomposition from elliptic harmonic forms).
Assume AC. For a compact smooth manifold the natural coefficient maps give for every degree, with all groups finite-dimensional, and the isomorphisms are natural and unital (Rational cohomology scalar comparison on compact smooth manifolds); AC is The Axiom of Choice.
Verification
The one-point space is a compact complex manifold of complex dimension zero, so by [F1] it has no forms of positive degree and its complex of complex-valued forms is in degree zero with zero differential; hence and for , and with all operators zero. By [F2] each degree-zero class has the unique smooth harmonic representative equal to the function with value , and is purely of type while both sides of the conjugation symmetry are this same space and all other Hodge pieces vanish.
By [F3], whose AC hypothesis is the Given, the natural coefficient map is an isomorphism, and its unitality sends the rational unit to the class of the function ; hence with rational structure spanning the type- piece, and for because the comparison is an isomorphism in every degree and the complex cohomology vanishes there.
By [F1] and , so is the identity operator on the one-dimensional space , which is the asserted degree-zero hard-Lefschetz map. For the polarization, on is -bilinear and nondegenerate (); it satisfies ; the type condition unless only involves the pair , where holds, so it is satisfied; and the Weil operator of the weight-zero structure is , so is positive definite Hermitian on . Therefore is a rational polarization of the rational pure Hodge structure , of weight zero, as claimed.
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Dependency tree · two levels
42 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- Pierre Deligne, Théorie de Hodge II, Publ. Math. IHES 40 (1971) 5-57; (2.1.10)-(2.1.17) printed pp. 26-27 (Hodge structures, Tate twist, orientations, polarizations), (2.2.1) printed p. 27 (spectral sequence of a compact Kähler manifold), Lemma (4.2.3) printed p. 44 (standard reference, not scraped)
- Christian Schnell, Complex Manifolds, MAT 545 (Stony Brook, Fall 2024), Class 18 'The Hodge decomposition' (October 31), 6 pp.; Corollaries 18.1-18.4, Theorem 18.5 (18.6), Corollary 18.7, Proposition 18.12 (∂∂̄-lemma), cohomological Lefschetz decomposition (standard reference, not scraped)
- Jean-Pierre Demailly, Complex Analytic and Differential Geometry, Chapter VI (Hodge Theory), §5.1-§5.3 and §6.1, printed pp. 300-306; (5.1)-(5.17) operators of Hermitian geometry, primitive elements and hard Lefschetz; (6.3)-(6.7) Kähler commutation identities (standard reference, not scraped)