type==DEFINITION){str=symbol.output+AMremoveCharsAndBlanks(str,symbol.input.length);symbol=AMgetSymbol(str);if(symbol==null||symbol.ttype==RIGHTBRACKET)
  return[null,str,null];}
  str=AMremoveCharsAndBlanks(str,symbol.input.length);switch(symbol.ttype){case SPACE:node=AMcreateElementMathML(symbol.tag);node.setAttribute(symbol.atname,symbol.atval);return[node,str,symbol.tag];case UNDEROVER:if(isIE){if(symbol.input.substr(0,4)=="\\big"){str="\\"+symbol.input.substr(4)+str;symbol=AMgetSymbol(str);symbol.ttype