 ring r=0,(x,y,z),dp;
poly f=2x3y+3z5;
diff(f,x);
==> 6x2y
vector v=[f,y2+z];
diff(v,z);
==> 15z4*gen(1)+gen(2)
ideal j=x2yz,xyz;
ideal i=x2,x2+yz,xyz;
// corresponds to differential operators
// d2/dx2, d2/dx2+d2/dydz, d3/dxdydz:
print(diff(i,j));
==> 2,0,
==> 1,x,
==> 0,1
// differentiation of rational functions:
ring R=(0,t),(x),dp;
number f = t^2/(1t)^2;
diff(f,t);
==> (2t)/(t33t2+3t1)
