LieAlgebraModule ++ LieAlgebraModule -- direct sum of LieAlgebraModules

i1 : g=simpleLieAlgebra("A",2)

o1 = LieAlgebra{isSimple => true   }
                LieAlgebraRank => 2
                RootSystemType => A

o1 : LieAlgebra

i2 : U=irreducibleLieAlgebraModule({4,2},g)

o2 = LieAlgebraModule{DecompositionIntoIrreducibles => HashTable{{4, 2} => 1}}
                      highestWeight => {4, 2}
                      isIrreducible => true
                      LieAlgebra => LieAlgebra{isSimple => true   }
                                               LieAlgebraRank => 2
                                               RootSystemType => A

o2 : LieAlgebraModule

i3 : V=irreducibleLieAlgebraModule({3,1},g)

o3 = LieAlgebraModule{DecompositionIntoIrreducibles => HashTable{{3, 1} => 1}}
                      highestWeight => {3, 1}
                      isIrreducible => true
                      LieAlgebra => LieAlgebra{isSimple => true   }
                                               LieAlgebraRank => 2
                                               RootSystemType => A

o3 : LieAlgebraModule

i4 : U++V

o4 = LieAlgebraModule{DecompositionIntoIrreducibles => HashTable{{3, 1} => 1}}
                                                                 {4, 2} => 1
                      isIrreducible => false
                      LieAlgebra => LieAlgebra{isSimple => true   }
                                               LieAlgebraRank => 2
                                               RootSystemType => A

o4 : LieAlgebraModule