code: private boolean isMathExpression(String line) {
          String cleanLine = cleanLine(line).trim();
          boolean mathExpression = false;
          if (cleanLine.startsWith(DEFINE)) {
              return true;
          } else if (cleanLine.matches(CODE_LINE_SUFFIX)) {
              return true;
          }
  
          // go forward
          int index = cleanLine.indexOf(COPYRIGHT_SYMBOL);
          for (int i = index + 1; i < cleanLine.length(); i++) {
              char c = cleanLine.charAt(i);
              if (c == Constants.OPEN_BRACKET || c == Constants.CLOSE_BRACKET || c == Constants.WHITESPACE_CHAR) {
                  continue;
              } else if (MATH_SYMBOLS.contains(c)) {
                  mathExpression = true;
                  break;
              } else {
                  break;
              }
          }
  
          // go backwards
          if (mathExpression) {
              for (int i = index - 1; i >= 0; i--) {
                  char c = cleanLine.charAt(i);
                  if (c == Constants.OPEN_BRACKET || c == Constants.CLOSE_BRACKET || c == Constants.WHITESPACE_CHAR) {
                      continue;
                  } else if (MATH_SYMBOLS.contains(c)) {
                      mathExpression = true;
                      break;
                  } else {
                      break;
                  }
              }
          }
          return mathExpression;
      }
docs: check if lines with (c) are actual copyright references of simple code lines