"Source: Text/Commut/RngDiff.text";
"Line: 3466";
"Date: Wed Sep 19 23:00:01 2018";
"Main: Thu May 25 10:02:38 2023";
// original file: Text/Commut/RngDiff.text, line: 3466
// Example: H118E61 ()
print "Example: H118E61";
ei := GetEchoInput();
SetEchoInput(true);
F<z> := RationalDifferentialField(Rationals());
R<D> := DifferentialOperatorRing(F);
L := D^2+z*D-3*z^2;
npgon, op := NewtonPolygon(L, Zeros(1/z)[1]);
op;
Differential(Parent(op));
Valuation($1,Zeros(1/z)[1]);
assert $1 eq -1;
faces:= Faces(npgon);
faces;
_<T> := PolynomialRing(Rationals());
NewtonPolynomial(faces[1]);
SetEchoInput(ei);
