


          Adding connectives

               To add a new connective press the  "connective"  button
          on  the  main  control  panel.  A  new  window should pop up
          labelled "xmagic: connectives". First type in a  symbol  for
          your  new  connective in the "symbol:" dialog box. Press the
          "accept"  button  under  the  box.  The  second  dialog  box
          labelled  "define connective" should now become active. Also
          you should see your symbol appearing to the left of the box.
          Now you should select whether you want your connective to be
          a constant, a unary connective (i.e., acting on one argument
          only)  or  a  binary  connective  (i.e., acting on two argu-
          ments).  Your choice will be reflected by a different string
          appearing  to  the left of the "define connective" box. That
          string also shows the letters you should use for  the  argu-
          ments  of  the connective. You should use "a" as an argument
          of a unary connective, and "a" and "b" as arguments  of  the
          binary connective.

               You can now type in a corresponding  formula.  To  send
          the  formula  to  MaGIC  press  the  second  "accept" button
          located under the "define connective:" dialog box. If  MaGIC
          accepts  your  formula  the newly defined connective will be
          placed in the list of defined connectives under  the  dialog
          boxes.  You  cannot  delete  a  connective  once it has been
          defined. When the "defined connectives:" table becomes  full
          both  dialog boxes in the upper part of the connectives win-
          dow will become insensitive. You can define up to 6 new con-
          nectives  at  a time. Pressing the "reset all" button on the
          main control panel will undefine  all  connectives  and  you
          will be able to start the definitions from the beginning.
