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Atlas.AlgebraicGeometryI.code.CohomologyAxiomsElimination

noncomputable def CohomologyAxiomsElimination.h1_O_defined (k : Type u_1) [Field k] (A : Type u_2) [CommRing A] [Algebra k A] :

Concrete definition of h^1(O) for an affine curve Spec A over k: the k-dimension of the Kähler differentials Ω_{A/k}.

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    Unfolds h1_O_defined to its definition as finrank Ω_{A/k}.

    On a Dedekind curve, the elimination definition of h^1(O) agrees with the official one.

    Concrete definition of h^1(skyscraper): zero, since the cohomology of a skyscraper sheaf vanishes in positive degree.

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      h1_sky_defined is definitionally zero.

      On a Dedekind curve, the elimination definition of h^1(skyscraper) agrees with the official one.

      The h^1(O) of the affine spectrum Spec R, computed from the abstract sheaf cohomology.

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        The h^0(O) of the affine spectrum Spec R, computed from the abstract sheaf cohomology.

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          The "grounded" Euler characteristic homomorphism ℤ × ℤ → ℤ for a Dedekind curve, built from the concrete h1_O_defined and h1_sky_defined values.

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            groundedCohChi C (1, 0) = 1 - g, recovering the structure sheaf contribution.

            groundedCohChi C (0, 1) = 1, the skyscraper contribution.

            The grounded Euler characteristic agrees with the official one on a Dedekind curve.

            Global sections of O_{Spec R} are R (alias).

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