DED is a preliminary version of an interactive system for deductive program
synthesis.
The user specifies the input assertion and the output goal and guides the system
to synthesize an applicative program that satisfy this specification.
For background read "The Deductive Approach to Program Synthesis" by Zohar Manna
and Richard Waldinger in ACM TOPLAS Jan 1980.

Run the program by typing  R DED. The system will respond by printing:
>

Now you may want to use one of: START, DECLARE, HELP.

If you find yourself in MACLISP. Try <CTRL>G and then (DED) hopefully your
derivation is still around.

Documentation is in DED.DOC[DED,YM]