"Source: Text/Group/GrpFP.text";
"Line: 5382";
"Date: Thu Sep 25 14:47:45 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Group/GrpFP.text, line: 5382
// Example: H80E42 ()
print "Example: H80E42";
ei := GetEchoInput();
SetEchoInput(true);
F<x,y> := FPGroup< x, y | x^3 = 1, y^3 = 1, (x*y)^4 = 1,
                        (y*y^x)^2 = y^x*y >;          
H<a,b> := sub<F | (x*y)^2, y >;
Index(F,H);
assert $1 eq 1;
H;
Rewrite(F, ~H);
H;
Order(DeleteRelation(H,5)) eq Order(H);
assert $1;
SetEchoInput(ei);
