Changes between Initial Version and Version 2 of Ticket #30245


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Timestamp:
08/01/20 02:06:16 (2 years ago)
Author:
mkoeppe
Comment:

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  • Ticket #30245 – Description

    initial v2  
    1 It inherits `_add_` and `_sub_` methods that make no sense in the coercion system.
     1It inherits `_add_` and `_sub_` methods that make no sense in the coercion system. These methods are guaranteed by the coercion system to get elements of the parent, and are supposed to give elements as well.
     2
     3Also other operations inherited from the module are problematic because they are not type-stable. The result of operations is supposed to depend only on the parents of the operands, but:
     4{{{
     5sage: 2 * a
     6Type-(1,1) tensor on the Rank-2 free module M over the Integer Ring
     7sage: -a
     8Automorphism of the Rank-2 free module M over the Integer Ring
     9sage: (-1)*a
     10Automorphism of the Rank-2 free module M over the Integer Ring
     11sage: 0 *a
     12Automorphism of the Rank-2 free module M over the Integer Ring
     13}}}
    214
    315(a) Instead, there should be a coercion map from `FreeModuleLinearGroup`, sending a `FreeModuleAutomorphism` to the underlying tensor.