Thank you for contributing this! Even without being integrated into
SAGE, this is very useful for me; I need these numbers reasonably
often, and I hate having to reconstruct the calculation from scratch
every time I need to do it.

Kiran

On Jan 14, 8:38 am, "D. Benjamin Antieau" <[EMAIL PROTECTED]>
wrote:
> To all,
>
> I've created a sage file to calculate, among other things, the Hodge numbers
> of an arbitrary complete intersection. Attached is the .sage file. I also
> attempted to create a .spkg file, but it does not seem to work. Mine
> contains simply a .py file that the install script puts it
> $SAGE_ROOT/local/bin. But, I cannot seem to use it from within sage. Any
> help on that front would be appreciated. On the other hand, loading the
> .sage file works fine.
>
> The file itself is well-documented. I would love suggestions for further
> methods to add. For instance, at some point I will add the ability to
> compute the degrees of the top Chern classes of a threefold.
>
> I don't see putting this in sage at the moment, but it does lead to the
> question: should there be a CompleteIntersection class, which would inherit
> from AlgebraicScheme_subscheme_projective. If so, then I could put this code
> in that class in the characteristic zero case.
>
> Ben Antieau
>
> Example:
>
> The Hodge numbers of a crazy fourfold. The list of integers is the list of
> degrees of the complete intersection.
>    sage: hodge_numbers_ci([2,4,6,3,6,4,3,2,9,5],4)
>    [          1           0           0           0  2658146543]
>    [          0           1           0 22238665343           0]
>    [          0           0 42452753184           0           0]
>    [          0 22238665343           0           1           0]
>    [ 2658146543           0           0           0           1]
>
> The file provides the following functions:
> chiy_characteristic_ci(degrees,index,yprecision,zprecision)
> hodge_numbers_ci(degrees,dimension)
> betti_numbers_ci(degrees,dimension)
> euler_characteristic_ci(degrees,dimension)
> topological_euler_characteristic_ci(degrees,dimension)
> arithmetic_genus_ci(degrees,dimension)
> geometric_genus_ci(degrees,dimension) [==arithmetic_genus_ci]
> K_squared_surface_ci(degrees,dimension) [computes the degree of K^2 of a
> complete intersection surface]
> c2_surface_ci(degrees,dimension) [computes the degree of the second Chern
> class of a complete intersection surface]
>
>  hodge_numbers_ci.sage
> 22KDownload
>
>  hodge_numbers_ci-0.1.spkg
> 5KDownload
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