Changes between Initial Version and Version 1 of Ticket #14353, comment 5


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Timestamp:
04/02/13 21:07:34 (9 years ago)
Author:
vbraun
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  • Ticket #14353, comment 5

    initial v1  
    11I don't think there are particularly good names for the intermediate fans. Instead of trying to invent some name, we can just let a user use `domain_fan()` / `image_fan()` on the factored morphism.
    22
    3 We have a choice for `Sigma_i`. Just the intersection with the image sublattice will in general contain cones whose preimage under `f_b` is empty. We can leave those out and get a smaller `Sigma_i`. E.g. take the composition of the half blowup chart with the embedding `C^2-> P^2`. The natural thing to do is probably take this smaller fan. So `f_i` would be the embedding `C^2->P^2` in the example.
     3We have a choice for `Sigma_i`. Just the intersection with the image sublattice will in general contain cones whose preimage under `f_b` is empty. We can leave (some of) those out and get a smaller `Sigma_i`. E.g. take the composition of the half blowup chart with the embedding `C^2-> P^2`. The natural thing to do is probably take this smaller fan. So `f_i` would be the embedding `C^2->P^2` in the example.
    44
    55I'm happy to get rid of `restrict_to_image`, I was tempted to do that myself....