The Mathcal template is intended to simulate a calligraphic font for use in mathematical formulas using standard HTML. Use this template as an alternative to \mathcal{...} in LaTeX markup (see Help:Displaying a formula).
The template is meant to be used with alphabetic text, typically one or a few capital letters. If the body contains an exposed equals-sign ("="), it will fail to render. For example, the following template use produces no result:
{{mathcal|P=NP}}.
There are two ways to resolve this.
Method 1: Start the body with "1=", as in:
{{mathcal|1=P=NP}},
which produces: P=NP.
Method 2: Enclose the equals-sign in double-braces "{{=}}", as in:
