Define unnumbered theorem with template ws-ijnt.cls

Question

The obsolete latex template ws-ijnt.cls (see here) is incompatible with amsthm, ntheorem and part of thmtools. How can I define an unnumbered theorem environment with this template?

Answer 1

This works:

\newtheorem{nonumberthm}{Theorem}
\renewcommand{\thenonumberthm}{\unskip}

Of course you don't want to set a \label in the body of such theorems. Well, you can do it, but using \ref would be meaningless.