"Source: Text/Commut/RngDiff.text";
"Line: 2755";
"Date: Thu Sep 25 14:47:46 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Commut/RngDiff.text, line: 2755
// Example: H121E49 ()
print "Example: H121E49";
ei := GetEchoInput();
SetEchoInput(true);
F<z> := RationalDifferentialField(Rationals());
R<D> := DifferentialOperatorRing(F);
pl := Zeros(z)[1];
Rcompl<Dcompl>, mp := Completion(R,pl);
IsDifferentialOperatorRing(Rcompl);
assert $1;
S<t> := BaseRing(Rcompl);
IsDifferentialLaurentSeriesRing(S);
assert $1;
mp(D);
Dcompl*t;
SetEchoInput(ei);
