M := RestrictionMatrix("A3",[1,0,0],"A1A1",[1,1]);

time res:=IrreducibleSimpleSubalgebrasOfSU(26);
t:=IrreducibleSimpleSubalgebraTreeSU(res,26);
t1:=Label(Vertices(t)!1);
t5:=Label(Vertices(t)!5);
names:=[j`algebra:j in [t1,t5]];
rds:=[RootDatum(j:Isogeny:="SC"):j in names];
vs:=[Eltseq(Matrix((j`weights)[1])):j in [t1,t5]];
decs:=[LieRepresentationDecomposition(rds[j],vs[j]):j in [1,2]];

time M1:=RestrictionMatrix(names[1],vs[1],names[2],vs[2]);
time M2:=RestrictionMatrix(rds[1],vs[1],rds[2],vs[2]);
time M3:=RestrictionMatrix(decs[1],decs[2]);

M1 eq M2;
M1 eq M3;

v:=[1] cat [0:i in [1..23]] cat [1]; //adjoint representation
time Branch(rds[1],rds[2],v,M1);


