#15300: Weyl and Clifford Algebras
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       Reporter:  tscrim             |        Owner:  tscrim
           Type:  enhancement        |       Status:  needs_review
       Priority:  major              |    Milestone:  sage-6.4
      Component:  algebra            |   Resolution:
       Keywords:  days54             |    Merged in:
        Authors:  Travis Scrimshaw   |    Reviewers:
Report Upstream:  N/A                |  Work issues:
         Branch:                     |       Commit:
  public/algebras/weyl_clifford-15300|  b47af6ae9f8dd1e6d870ec986f81fb6913d12e16
   Dependencies:  #16037             |     Stopgaps:
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Comment (by tscrim):

 Replying to [comment:141 jhpalmieri]:
 > When do I need to do `dx,dy,dz = sorted(W.differentials(), key=str)` vs.
 `dx,dy,dz = W.differentials()`? There are examples of both sorts; is the
 second version ever safe? I've seen in my own testing that the `variables`
 method can return its elements in a random order, not necessarily
 alphabetical. Will the same happen with `differentials` or
 `algebra_generators`? It's nice that `W.inject_variables()` works well;
 maybe that should be advertised, or at least used in some examples.

 The question is do we want to return a `Family` indexed by the variable
 names, which makes it act like a `dict` and have some specified order of
 output, or act like a list where the ordered of the output is the order of
 the input.

 There's actually somewhat of mismatch and that `algebra_generators` should
 match the behavior of `variables` and `differentials`. The reason why
 `inject_variables` works is because of a specified order of `gens`, not
 `algebra_generators` (which would also be tweaked accordingly).

 I'm bias towards making the outputs being indexed since it carries more
 information. However I do agree with adding examples demonstrating
 `inject_variables` and other similar constructions. Your thoughts?

 > When does `_coerce_map_from_` return a map and not just True or False?
 Please add more explanation and an example.

 This is the design of the function, and if it returns `True`, then
 `coerce_map_from` creates a map using `_element_constructor_`. There are
 times when it's easier/better-design to implement a custom morphism (like
 for a module with basis using `module_morphism`).

--
Ticket URL: <http://trac.sagemath.org/ticket/15300#comment:142>
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