"Source: Text/LieTheory/RootDtm.text";
"Line: 3012";
"Date: Fri Sep 26 12:10:11 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/LieTheory/RootDtm.text, line: 3012
// Example: H107E31 ()
print "Example: H107E31";
ei := GetEchoInput();
SetEchoInput(true);
RGL := StandardRootDatum( "A", 3 );
RPGL := RootDatum( "A3" );
A := VerticalJoin( SimpleRoots(RGL), Vector([Rationals()|1,1,1,1]) )^-1 *
  VerticalJoin( SimpleRoots(RPGL), Vector([Rationals()|0,0,0]) );
B := VerticalJoin( SimpleCoroots(RGL), Vector([Rationals()|1,1,1,1]) )^-1 *
  VerticalJoin( SimpleCoroots(RPGL), Vector([Rationals()|0,0,0]) );
phi := hom< RGL -> RPGL | A, B >;
v := Coroot(RGL,1); 
v; phi(v);
SetEchoInput(ei);
