#8044: Categories for finite/permutation/symmetric groups
---------------------------------+------------------------------------------
Reporter: nthiery | Owner: nthiery
Type: enhancement | Status: needs_review
Priority: major | Milestone: sage-4.3.2
Component: group_theory | Keywords: Finite groups, permutation
groups, symmetric groups
Author: Nicolas M. Thiéry | Upstream: N/A
Reviewer: | Merged:
Work_issues: |
---------------------------------+------------------------------------------
Description changed by nthiery:
Old description:
> This patch:
>
> - Introduces two new categories: FiniteGroups and
> FinitePermutationGroups
> - As a result, this standardizes the interface of those groups
> (cardinality, one, ...).
>
> - Puts all permutation groups and some other finite groups in the
> corresponding categories. There remains to handle finite matrix
> groups and Galois groups in sage/rings/number_field/.
>
> - Deprecates the class sage.groups.group.FiniteGroup. Content moved
> to the FiniteGroups category; this was essentially the cayley_graph
>
> - Merges cayley_graph with that for FiniteSemigroups. In the merging,
> ``connecting_set`` was deprecated to ``generators``. Also providing
> a single element by itself as connecting set is no more supported.
> Finally the default is side = "right" (was "twosided" for
> semigroups). This method is also generalized to Semigroups with an
> ``elements`` option (should this be vertices?).
>
> Why do we care about the produced graph using implementation =
> "networkx"?
> I would tend to remove this implementation detail; this would
> change the order of the edges, which requires fixing a test in
> sage.graphs.generic_graphs
>
> - Provides group_generators defined from gens, as well as
> semigroup_generators defined from group_generators in the finite
> and coxeter cases.
>
> - Also puts the SymmetricGroup in the FiniteWeylGroups category.
> Beware: unusual product convention
> Beware: this changes the generators to the standard Weyl group
> generators, that is the elementary transpositions
> - Adds an has_descent method to permutation group elements
>
> - Make all named permutation groups have UniqueRepresentation
> - Questionable: the underlying set of an alternating or symmetric
> group is now a tuple. This is safer and helps UniqueRepresentation.
> However, this could break backward compatibility. Also, maybe we
> want to keep the output as SymmetricGroup([1,3,4])?
>
> - Makes more systematic use of TestSuite(...).run()
> - Makes a minor improvement to FiniteEnumeratedSets tests for
> large finite enumerated sets
> - Strips away unused imports
> - Updates a couple doctests here and there
New description:
This patch:
* Introduces two new categories: FiniteGroups and FinitePermutationGroups
* Puts all permutation groups and some other finite groups in the
corresponding categories. There remains to handle finite matrix groups and
Galois groups in sage/rings/number_field/.
* As a result, this standardizes the interface of those groups
(cardinality, one, ...).
* Deprecates the class sage.groups.group.[wiki:FiniteGroup]. Content
moved to the FiniteGroups category; this was essentially the cayley_graph
* Merges cayley_graph with that for FiniteSemigroups. In the merging,
connecting_set was deprecated to generators. Also providing a single
element by itself as connecting set is no more supported. Finally the
default is side = "right" (was "twosided" for semigroups). This method is
also generalized to Semigroups with an elements option (should this be
vertices?).
Why do we care about the produced graph using implementation =
"networkx"? I would tend to remove this implementation detail; this would
change the order of the edges, which requires fixing a test in
sage.graphs.generic_graphs
* Provides group_generators defined from gens, as well as
semigroup_generators defined from group_generators in the finite and
coxeter cases.
* Also puts the SymmetricGroup in the FiniteWeylGroups category. Beware:
unusual product convention Beware: this changes the generators to the
standard Weyl group generators, that is the elementary transpositions
* Adds an has_descent method to permutation group elements
* Make all named permutation groups have UniqueRepresentation
* Questionable: the underlying set of an alternating or symmetric group
is now a tuple. This is safer and helps UniqueRepresentation. However,
this could break backward compatibility. Also, maybe we want to keep the
output as SymmetricGroup([1,3,4])?
* Makes more systematic use of TestSuite(...).run()
* Makes a minor improvement to FiniteEnumeratedSets tests for large
finite enumerated sets
* Strips away unused imports
* Updates a couple doctests here and there
--
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/8044#comment:4>
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