@mbork I'd normally agree, but this is definitely a duplicate of the symbol look up question, which is why I just commented to check with the OP first before voting to close, but it looks like egreg has already closed it.
– Adam LiterOct 28 '14 at 15:56
\mathfrak{S}, which requiresamssymb? – Adam Liter Oct 28 '14 at 15:29