#5502: [with patch, needs review] implement ascii art output for Dynkin diagrams
---------------------------+------------------------------------------------
Reporter: AlexGhitza | Owner: mhansen
Type: enhancement | Status: new
Priority: major | Milestone: sage-combinat
Component: combinatorics | Keywords: dynkin diagram ascii art lie
---------------------------+------------------------------------------------
Comment(by bump):
I think the spirit of this patch is the same as #2023.
The idea of this patch is just that if the Cartan type is that
of a classical Lie algebra, you should be able to ''somehow''
access it's Dynkin diagram. The solution here is making it part of the
string
returned by the {{{__repr__}}} method of the class.
We follow the Bourbaki conventions, which is the same as the
programmed-in Cartan types. These diagrams are identical to
those produced by LiE, so you can have them already if you
install that optional package.
{{{
sage: CartanType("E6").dynkin_diagram()
O 2
|
|
O---O---O---O---O
1 3 4 5 6
E6
}}}
You want this if you need to be reminded of what labeling
convention is used. If the Cartan type is not recognized, we get the
old behavior. Thus:
{{{
sage: CartanType(['E',6,1]).dynkin_diagram()
Dynkin diagram of type ['E', 6, 1]
}}}
It might be more convenient if untwisted affine types gave the
extended Dynkin diagram, thus:
{{{
sage: CartanType(['E',6,1]).dynkin_diagram()
O 0
|
|
O 2
|
|
O---O---O---O---O
1 3 4 5 6
E6~
}}}
Beyond that, one might implement Dynkin diagrams for twisted
affine types, but that seems less urgent.
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/5502#comment:6>
Sage <http://sagemath.org/>
Sage - Open Source Mathematical Software: Building the Car Instead of
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