+The core infrastructure of {\MathQL}.4 defines a syntax for queries
+(\figref{QueryTS}, production \GP{query}) and a syntax for results
+(\figref{ResultTS}, production \GP{avs}).
+A syntax extension for the most common functions of the basic library is
+also provided for the user's convenience and for backward compatibility with
+{\MathQL}.3. The syntax extension concerning the functions covered in this
+paper is shown in \figref{BasicTS}.
+Note that this extension makes \GP{avs} an instance of \GP{xavs}.
+
+