doc-src/System/symbols.tex

 
 Isabelle supports an infinite number of non-ASCII symbols, which are
 represented in source text as \verb,\<,$name$\verb,>, (where $name$ may be any
 identifier).  It is left to front-end tools how these symbols are presented to
 the user.  The following predefined standard symbols are available by default
-for Isabelle document output; they are also supported by Proof~General when
-used together with the X-Symbol package.
+for Isabelle document output; most of these are also supported by
+Proof~General when used together with the X-Symbol package.
 
 \begin{center}
   \input{syms}  
 \end{center}