;;; *****************************************************************

;;; Answers to Questions about Fuzzy Logic and Fuzzy Expert Systems *

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;;; Written by Mark Kantrowitz, Erik Horstkotte, and Cliff Joslyn

;;; fuzzy.faq


This FAQ is posted once a month on the 13th of the month. In between postings, the latest version of this FAQ is available by anonymous ftp from CMU:

To obtain the files from CMU, connect by anonymous FTP to

ftp.cs.cmu.edu:/user/ai/pubs/faqs/fuzzy/ []

using username "anonymous" and password "name@host" (substitute your email address) or via AFS in the Andrew File System directory /afs/cs.cmu.edu/project/ai-repository/ai/pubs/faqs/fuzzy/ and get the file fuzzy.faq.


You can also obtain a copy of the FAQ by sending a message to ai+query@cs.cmu.edu with

Send Fuzzy FAQ in the message body.

The FAQ postings are also archived in the periodic posting archive on rtfm.mit.edu:/pub/usenet/news.answers/fuzzy-logic/ [] If you do not have anonymous ftp access, you can access the archive by mail server as well. Send an E-mail message to ail-server@rtfm.mit.edu with "help" and "index" in the body on separate lines for more information.


An automatically generated HTML version of the Fuzzy Logic FAQ is accessible by WWW as part of the AI-related FAQs Mosaic page. The URL for this resource is


The direct URL for the Fuzzy FAQ is



If you need to cite the FAQ for some reason, use the following format:

Mark Kantrowitz, Erik Horstkotte, and Cliff Joslyn, "Answers to Frequently Asked Questions about Fuzzy Logic and Fuzzy Expert Systems",

comp.ai.fuzzy, <month>, <year>, ftp.cs.cmu.edu:/user/ai/pubs/faqs/fuzzy/fuzzy.faq,



*** Table of Contents:


[1] What is the purpose of this newsgroup?

[2] What is fuzzy logic?

[3] Where is fuzzy logic used?

[4] What is a fuzzy expert system?

[5] Where are fuzzy expert systems used?

[6] What is fuzzy control?

[7] What are fuzzy numbers and fuzzy arithmetic?

[8] Isn't "fuzzy logic" an inherent contradiction?

Why would anyone want to fuzzify logic?

[9] How are membership values determined?

[10] What is the relationship between fuzzy truth values and probabilities?

[11] Are there fuzzy state machines?

[12] What is possibility theory?

[13] How can I get a copy of the proceedings for <x>?

[14] Fuzzy BBS Systems, Mail-servers and FTP Repositories

[15] Mailing Lists

[16] Bibliography

[17] Journals and Technical Newsletters

[18] Professional Organizations

[19] Companies Supplying Fuzzy Tools

[20] Fuzzy Researchers

[21] Elkan's "The Paradoxical Success of Fuzzy Logic" paper

[22] Glossary

[24] Where to send calls for papers (cfp) and calls for participation


Search for [#] to get to topic number # quickly. In newsreaders which

support digests (such as rn), [CNTL]-G will page through the answers.