75.4 PrintDynkinDiagram

PrintDynkinDiagram( type )

PrintDynkinDiagram( D )

This is a purely descriptive routine, which, by printing the Dynkin diagram of a type type (the result of CartanType) shows how the generators of the corresponding group are labeled on its Dynkin diagram.

    gap> C := [ [ 2, 0, -1 ], [ 0, 2, 0 ], [ -1, 0, 2 ] ];;
    gap> t := CartanType( C );
    [ [ "A", [ 1, 3 ] ], [ "A", [ 2 ] ] ]
    gap> PrintDynkinDiagram( t );
    A2    1 - 3
    A1    2
    gap> PrintDynkinDiagram( CartanType( CartanMat( "E", 8) ) );
    E8          2             
                

   
        1 - 3 - 4 - 5 - 6 - 7 - 8 

The argument to PrintDynkinDiagram can also be a domain (i.e., D should be a record with a field operations.PrintDynkinDiagram, and that function is then called with D as argument --- this is used for Coxeter groups and Coxeter cosets).

This function requires the package "chevie" (see RequirePackage).

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