anchor.diff:  \large,{\large AaBb123}
   \lbrace,
   \lceil,
  -\ldots,
   \leadsto,
   \left,\left\lbrace \frac ab, c \right\rbrace
   \leftarrow,
  
positive.code: \Doteq,
  \doteqdot,
  \dotplus,
  \dots,x_1 + \dots + x_n
  \dotsc,"x,\dotsc,y"
  \dotsm, (x+1)\dotsm(y-1)
  \doublebarwedge,
  \doublecap,
  \doublecup,
  
negative.code: #,\def\specialFrac#1#2{\frac{x + #1}{y + #2}}
  %,%this is a single-line comment
  &,"\begin{matrix}
  a & b\cr
  c & d
  \end{matrix}"
  ^,x^i
  _,x_i
  {,\{
  