dynkinType(BasicList) -- constructing a Dynkin type

Function: dynkinType
Usage:

dynkinType(L)
Inputs:
- L, a basic list, of irreducible types that are lists containing a string of one letter from A to F and a positive integer, the rank
Outputs:
- an instance of the type DynkinType,

Description

i1 : dynkinType({{"A",2},{"B",3}})

o1 = DynkinType{{A, 2}, {B, 3}}

o1 : DynkinType

Note that low rank isomorphisms between classical groups are automatically used so that the letter is alphabetically minimal and the elementary types are irreducible (D2=A1xA1).

i2 : dynkinType({{"A",2},{"B",1}})

o2 = DynkinType{{A, 2}, {A, 1}}

o2 : DynkinType

i3 : dynkinType({{"A",2},{"C",2}})

o3 = DynkinType{{A, 2}, {B, 2}}

o3 : DynkinType

i4 : dynkinType({{"A",2},{"D",2}})

o4 = DynkinType{{A, 2}, {A, 1}, {A, 1}}

o4 : DynkinType

Ways to use this method:

dynkinType(BasicList) -- constructing a Dynkin type

The source of this document is in WeylGroups.m2:4053:0.