ACL2 Version 6.4

ACL2 is both a programming language in which you can model computer systems and a tool to help you prove properties of those models.

ACL2 is part of the Boyer-Moore family of provers, for which its authors have received the 2005 ACM Software System Award.


Start Here: Applications, Tours, and Tutorials/Demos ACL2 Workshops, UT Seminar, and Course Materials
Publications about ACL2 and Its Applications The User's Manual and Hyper-Card
Community Books: Lemma Libraries and Utilities Mailing Lists
Recent changes to this page Obtaining, Installing, and License
Differences from Version 6.3 Other Releases

Matt Kaufmann and J Strother Moore
University of Texas at Austin
January 9, 2014

Welcome to the ACL2 home page! We highlight a few aspects of ACL2:

We gratefully acknowledge substantial support from the following. (These are included in a much more complete acknowledgments page.)

The User's Manual

ACL2's user manual is a vast hypertext document. If you are a newcomer to ACL2, we do not recommend that you wander off into the full documentation. Instead start with the ACL2-TUTORIAL documentation topic. Experienced users tend mostly to use the manual as a reference manual, to look up concepts mentioned in error messages or vaguely remembered from their past experiences with ACL2.

The ACL2+books combined manual includes not only ACL2 User's Manual, but also documents many of the community books (libraries). This manual, which is written by many authors, is thus more extensive than the ACL2 system, and thus potentially more useful.

The following links take you to these two manuals. The manuals can however be read not only in a Web browser, but in the ACL2-Doc Emacs browser or by using the ACL2 :DOC command at the terminal; see the documetation topic, DOCUMENTATION.

Once you have installed ACL2, you can browse the ACL2 User's Manual locally by opening the home page in your browser to view the file doc/home-page.html in your ACL2 sources directory.

Community Books: Lemma Libraries and Utilities, and How to Contribute

A companion to ACL2 is the library of community books, which have been developed by many users over the years. These books contain definitions and theorems that you might find useful in your models and proofs. In addition, some books contain ACL2 reasoning or analysis tools built by users. The installation instructions explain how to download and install the community books.

We strongly encourage users to submit additional books or improve existing books, by following the instructions at the acl2-books project page. In particular, the community book books/system/doc/acl2-doc.lisp contains the ACL2 system documentation. Members of the acl2-books project are welcome to edit that book in order to improve the system documentation.

We also distribute a few interface tools. For these, see the Utilities section of Books and Papers about ACL2 and Its Applications. Some of the papers mentioned in that collection contain utilities, scripts, or ACL2 books for the problem domains in question.

Searching documentation and books

The links below may help you to search the ACL2 documentation and the ACL2 community books, respectively. Our approach is low-tech, but intended to be reliable and easy to use on any platform. You might want to add a bookmark for each of these.