I wish to define an operator, something like:

\DeclareMathOperator{\St}{\overline{St}} 

It works partially, however the spacing between the operator and the next symbol disappears.

May I ask how to correct this? I tried doing:

\DeclareMathOperator{\St}{\mathop{\overline{St}}} 

enclosing a \mathop as suggested in Why does \overline mess up the spacing?. However, it doesn't seem to work in this context.

Thanks for any help.

Update: Sorry, my bad, I put a curly bracket {\St} in my code, which causes the spacing to disappear. Removing the curly bracket solves the issue.