"Source: Text/Commut/RngDiff.text";
"Line: 2354";
"Date: Thu Sep 25 14:47:46 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Commut/RngDiff.text, line: 2354
// Example: H121E41 ()
print "Example: H121E41";
ei := GetEchoInput();
SetEchoInput(true);
S<t> := DifferentialLaurentSeriesRing(Rationals());
R<D> := DifferentialOperatorRing(S);
L := D^2 + 2*t;
P := O(t)*D^3 + (1+O(t))*D^2  + 2*t;
Order(L);
assert $1 eq 2;
Degree(P);
assert $1 eq 3;
L eq P;
assert not $1;
IsWeaklyEqual(L,P);
assert $1;
WeakOrder(P);
assert $1 eq 2;
SetEchoInput(ei);
