Root system data for (untwisted) type A affine

class sage.combinat.root_system.type_A_affine.CartanType(n)

Bases: sage.combinat.root_system.cartan_type.CartanType_standard_untwisted_affine

EXAMPLES:

sage: ct = CartanType(['A',4,1])
sage: ct
['A', 4, 1]
sage: ct._repr_(compact = True)
'A4~'

sage: ct.is_irreducible()
True
sage: ct.is_finite()
False
sage: ct.is_affine()
True
sage: ct.is_untwisted_affine()
True
sage: ct.is_crystallographic()
True
sage: ct.is_simply_laced()
True
sage: ct.classical()
['A', 4]
sage: ct.dual()
['A', 4, 1]

sage: ct = CartanType(['A', 1, 1])
sage: ct.is_simply_laced()
False
sage: ct.dual()
['A', 1, 1]

TESTS:

sage: TestSuite(ct).run()
ascii_art(label=<function <lambda> at 0x7fb30a1ba500>)

Returns a ascii art representation of the extended Dynkin diagram

EXAMPLES:

sage: print CartanType(['A',3,1]).ascii_art()
0
O-------+
|       |
|       |
O---O---O
1   2   3

sage: print CartanType(['A',5,1]).ascii_art(label = lambda x: x+2)
2
O---------------+
|               |
|               |
O---O---O---O---O
3   4   5   6   7

sage: print CartanType(['A',1,1]).ascii_art()
O<=>O
0   1

sage: print CartanType(['A',1,1]).ascii_art(label = lambda x: x+2)
O<=>O
2   3
dual()

Type \(A_1^1\) is self dual despite not being simply laced.

EXAMPLES:

sage: CartanType(['A',1,1]).dual()
['A', 1, 1]
dynkin_diagram()

Returns the extended Dynkin diagram for affine type A.

EXAMPLES:

sage: a = CartanType(['A',3,1]).dynkin_diagram()
sage: a
 0
 O-------+
 |       |
 |       |
 O---O---O
 1   2   3
 A3~
sage: sorted(a.edges())
[(0, 1, 1),
 (0, 3, 1),
 (1, 0, 1),
 (1, 2, 1),
 (2, 1, 1),
 (2, 3, 1),
 (3, 0, 1),
 (3, 2, 1)]

sage: a = DynkinDiagram(['A',1,1])
sage: a
O<=>O
0   1
A1~
sage: sorted(a.edges())
[(0, 1, 2), (1, 0, 2)]

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