"Source: Text/Commut/RngDiff.text";
"Line: 1081";
"Date: Thu Sep 25 14:47:46 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Commut/RngDiff.text, line: 1081
// Example: H121E18 ()
print "Example: H121E18";
ei := GetEchoInput();
SetEchoInput(true);
F<z> := RationalDifferentialField(Rationals());
Derivative(z^2);
K, toK := ChangeDerivation(F, z);
K;
toK;
Derivative(toK(z^2));
UnderlyingRing(F) eq UnderlyingRing(K);
assert $1;
SetEchoInput(ei);
