# Dt acting on symbolic notational forms

This one must be simple, but I can't figure out a decent solution.

Suppose, I have a symbol with a notational form applied to it, say OverHat[A]. Now, if I didn't specify anything about A, I would expect Dt[OverHat[A]] staying unevaluated.

But in reality OverHat gets evaluated: Dt[OverHat[A]] (* ---> Dt[A] Derivative[1][OverHat][A] *)

What are possible ways to prevent this from happening?

EDIT

To state more clearly, I want OverHat[A] to behave like ordinary symbol under action of Dt:

Dt[symb] (* ---> Dt[symb] *)

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...but you are differentiating with respect to what? Anyway, have a look at the Constants option of Dt[]. – J. M. May 17 '13 at 10:16
@J. M., Dt[OverHat[A]] is a total differential of OverHat[A] in my case. Setting A (or even OverHat) to a constant doesn't work, it just gives zero. – SaF May 17 '13 at 10:26
@SaF You mean HoldForm@Dt[OverHat[A]] ? (BTW, setting A to a constant of course cause 0, since Dt[A]=0 in this case.) – luyuwuli May 17 '13 at 10:39
@luyuwuli, HoldForm is a possible workaround, but this way the head of my expression will be HoldForm, which is unwanted. I want OverHat[A] to be treated like an ordinary unspecified symbol by Dt, e.g. Dt[OverHat[A]]=Dt[OverHat[A]] – SaF May 17 '13 at 10:44
How about using a new symbol like overA in place of OverHat[A]? The problem is that OverHat is a typesetting function (like MatrixForm or Subscript) and you're trying to make it do something it isn't intended to do. – bill s May 17 '13 at 11:11

The official way of solving such notational problems is to use the following package:

Needs["Notation"]

Symbolize[
ParsedBoxWrapper[
OverscriptBox["A", "^"]]]
`

Now you can enter the notation in the usual way to get this:

You have to do this for every hat-symbol individually, though.

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Thanks, I'll check it out. – SaF May 17 '13 at 22:21