hi i have one question
in maple is many function which can have two 2D output like sum:
Sum(f,i=3..n); in 2d Sum(f,i=3..n);
sum(f,i=3..n); in 2d (n-2)f;
for example i wanna my own function which will has two forms like a sum but in unevalued form will be instead of sigma for example Q or another symbol and above and belove that symbol will be some values, and in evaluated form there will be expression or number;
another example is Diff or BesselJ funcions which have both two forms (symbolic/algebraic)
my question is how to make this?
but Q have to has a size like sigma in sum and 2,4 size as indexes...
i thing there is possibility to define a typesetting rule but I don't know how...