Rules in (and for) the Web have become a mainstream topic since they
were marked up for E-Commerce, were identified as a Semantic Web
design issue, and were put to practice for document generation from a
central XML repository. Rules have also continued to play an important
role in Intelligent Agents and AI shells for knowledge-based systems,
which need a Web interchange format, too.

The Rule Markup Initiative has taken initial steps towards defining a
shared Rule Markup Language (RuleML), permitting both forward
(bottom-up) and backward (top-down) rules in XML for deduction,
rewriting, and further inferential-transformational tasks. The
initiative started during PRICAI 2000, and is currently continuing
through direct contacts and the Internet. A Rule Markup Workshop is
planned in conjunction with the third International Conference on
Electronic Commmerce, ICEC2001, in Vienna, Austria, in October 2001.

The participants of the RuleML Initiative constitute an open network
of individuals and groups from both industry and academia. We are not
commencing from zero but have done some work related to rule markup or
have actually proposed some specific tag set for rules. Our main goal
is to provide a basis for an integrated rule-markup approach that will
be beneficial to all involved and to the rule community at large.

Rules can be stated (1) in natural language, (2) in some formal notation,
or (3) in a combination of both. Being in the third, 'semiformal'
category, the RuleML Initiative is working towards an XML-based
markup language that permits Web-based rule storage, interchange,
retrieval, and firing/application.

RuleML example with prem/conc-embedded XHTML
(English premise and semiformal conclusion):

<rule>
  <prem>
    <p>You want to review rule principles</p>
  </prem>
  <conc>
    <p>You may look at
      <a href="http://www.cs.brandeis.edu/...">Rule-Based Systems</a>
    </p>
  </conc>
</rule>

Further info on Goals, Uses, Scope, Participants, Steps, and Contact
can be found at the RuleML Homepage: http://www.dfki.de/ruleml

If you are interested to join this initiative, please send a link
describing your work related to rule markup to some or all of the
current participants.

Cheers,

Danny.

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<?xml version='1.0' encoding='UTF-8'?>

<!DOCTYPE domain SYSTEM "kex.dtd">

<domain name="Test Data">

<!-- *** facts *** -->

<fact goal="true">Stone</fact>

<fact goal="true">Helicopter</fact>

<fact goal="true">Bird</fact>

<fact goal="true">Mouse</fact>

<fact question="true">Is it alive</fact>

<fact question="true">Can it fly</fact>

<fact>alive</fact>

<!-- *** rules *** -->

<rule>

<fact>Helicopter</fact>

<condition negated="true">alive</condition>

<condition>Can it fly</condition>

</rule>

<rule>

<fact>Stone</fact>

<condition negated="true">alive</condition>

<condition negated="true">Can it fly</condition>

</rule>

<rule>

<fact>Mouse</fact>

<condition negated="true">Can it fly</condition>

<condition>alive</condition>

</rule>

<rule>

<fact>alive</fact>

<condition>Is it alive</condition>

</rule>

</domain>

-------------------------------------------

<?xml encoding="UTF-8"?>

<!-- DTD for KVM Expert System Knowledge Base Domains -->

<!ELEMENT domain (fact+,rule+)>

<!ATTLIST domain name CDATA #REQUIRED>

<!ELEMENT fact (#PCDATA)>

<!ATTLIST fact goal (true | false) "false">

<!ATTLIST fact question (true | false) "false">

<!ATTLIST fact negated (true | false) "false">

<!ELEMENT rule (fact,condition+)>

<!ELEMENT condition (#PCDATA)>