Class notes: Recursion and Induction, CS 389r
3/26/07
Matt Kaufmann

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The workhorses of the ACL2 theorem prover are its rewriter and, to some
extent, its automated induction>.

Today's demos:

  

  LOG FILE

  First demo

  
Primary solution to Problem 101

  Alternate solution to Problem 101 using
  ordinals books.

  Triple-reverse tutorial example:
    
    Demo on the web
    Source
    file (certifiable book)
    

  


We also stressed the use of the documentation



Miscellaneous notes

ACL2s (Eclipse interface to
ACL2) may be helpful if you don't know emacs.  But if you want to learn emacs,
you might start with this little emacs cheat
sheet.



If you do know emacs, I suggest putting the following in your
.emacs file, and perhaps reading the documentation at the top of
that file.

(load "/projects/acl2/current/emacs/emacs-acl2.el")




For proof trees, see documentation
for topic proof-tree.  In a nutshell:



In emacs:
meta-x start-proof-tree

In ACL2:
:start-proof-tree

Then control-z c to jump to the next checkpoint.



:INDUCT hints

Suppose we want as an inductive case:

(implies (and (consp x)
              (foo (cdr x) (g x y)))
         (foo x y))


We can do this:

(defstub g (x y) t)

(defun foo-induction (x y)
  (if (consp x)
      (foo-induction (cdr x) (g x y))
    (list x y)))

(defstub foo (x y) t)

(thm (foo x y)
     :hints (("Goal" :induct (foo-induction x y))))

Class notes: Recursion and Induction, CS 389r3/26/07Matt Kaufmann

Miscellaneous notes

:INDUCT hints

Class notes: Recursion and Induction, CS 389r
3/26/07
Matt Kaufmann

`:INDUCT` hints