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    • CommentRowNumber1.
    • CommentAuthorUrs
    • CommentTimeNov 19th 2020

    starting something

    v1, current

    • CommentRowNumber2.
    • CommentAuthorUrs
    • CommentTimeNov 20th 2020
    • (edited Nov 20th 2020)

    added this pointer:

    diff, v2, current

    • CommentRowNumber3.
    • CommentAuthorUrs
    • CommentTimeNov 20th 2020

    added pointer to:

    diff, v2, current

    • CommentRowNumber4.
    • CommentAuthorUrs
    • CommentTimeNov 20th 2020
    • (edited Nov 20th 2020)

    added the statement that

    the SU-bordism ring is spanned by classes of Calabi-Yau manifolds: in particular the K3 surface in degree 4 and certain CY 3-folds and CY4-folds in degrees 6 and 8.

    Will give this statement its own little entry now (Calabi-Yau manifolds in SU-bordism theory), for ease of cross-linking in the entries K3 surface and Calabi-Yau manifold

    diff, v2, current

    • CommentRowNumber5.
    • CommentAuthorUrs
    • CommentTimeNov 20th 2020

    added pointer to:

    diff, v3, current

    • CommentRowNumber6.
    • CommentAuthorUrs
    • CommentTimeNov 20th 2020

    added these statements:


    The kernel of the forgetful morphism

    Ω SUΩ U \Omega^{SU}_\bullet \longrightarrow \Omega^{\mathrm{U}}_\bullet

    from the SU-bordism ring to the complex bordism ring, is pure torsion.

    Every torsion element in the SU-bordism ring Ω SU\Omega^{SU}_\bullet has order 2.

    diff, v3, current

    • CommentRowNumber7.
    • CommentAuthorUrs
    • CommentTimeNov 20th 2020

    and this one:


    The torsion subgroup of the SU-bordism ring is concentrated in degrees 8k+18k+1 and 8k+28k+2, for kk \in \mathbb{N}.

    diff, v3, current

    • CommentRowNumber8.
    • CommentAuthorUrs
    • CommentTimeJan 9th 2021

    added pointer to:

    diff, v7, current

    • CommentRowNumber9.
    • CommentAuthorUrs
    • CommentTimeFeb 18th 2021
    • (edited Feb 18th 2021)

    I have made explicit the corollary (here) that the image of the element [K3][K3] of Ω 4 SU\Omega^{SU}_4 is still non-trivial in Ω 4 U\Omega^{\mathrm{U}}_4.

    (This must be well-known, but I have trouble finding a reference that says it more directly. A half-sentence in Novikov 86, p. 216 (218 of 321) suggests this, without, however, really saying so, much less proving it.)

    diff, v10, current

    • CommentRowNumber10.
    • CommentAuthorUrs
    • CommentTimeFeb 18th 2021

    added pointer to:

    for (the failure of) the Conner-Floyd isomorphism for MSUKOMSU \to KO.

    diff, v11, current

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