Symbols:Fonts/mathcal/Lowercase

Font Description
The lowercase letters of the alphabet rendered in the mathcal font are:
 * $\mathcal {a \ b \ c \ d \ e \ f \ g \ h \ i \ j \ k \ l \ m \ n \ o \ p \ q \ r \ s \ t \ u \ v \ w \ x \ y \ z}$

Hence the lowercase letters are not implemented in mathcal, the presentation defaulting to mathit.