"Source: Text/Commut/RngDiff.text";
"Line: 1113";
"Date: Thu Sep 25 14:47:46 2025";
"Main: Fri Sep 26 14:29:19 2025";
// original file: Text/Commut/RngDiff.text, line: 1113
// Example: H121E19 ()
print "Example: H121E19";
ei := GetEchoInput();
SetEchoInput(true);
F<z> := RationalDifferentialField(Rationals());
df := Differential(1/z);
df in DifferentialSpace(UnderlyingRing(F));
assert $1;
M<u>, mp := ChangeDifferential(F,df);
IsAlgebraicDifferentialField(M);
assert $1;
Domain(mp) eq F and Codomain(mp) eq M;
assert $1;
Differential(M);
mp(z);
Derivation(M)(u);
Derivation(F)(z);
assert $1 eq 1;
dg := Differential(z^3+5);
N<v>, mp := ChangeDifferential(F,dg);
Differential(M);
mp(z);
Derivation(N)(mp(z));
SetEchoInput(ei);
