Negation As Failure

Negation-as-failure (Naf) has first been implemented in OO jDREW TD (version 0.88), and recently introduced into OO jDREW BU for stratified programs.

For example, 

<Assert>
   <And>

      <Implies closure="universal">
         <And>
            <Atom>
               <Rel>premium</Rel>
               <Var>customer</Var>
            </Atom>
            <Atom>
               <Rel>onsale</Rel>
               <Var>product</Var>
            </Atom>
            <Naf>
               <Atom>
                  <Rel>special</Rel>
                  <Var>product</Var>
               </Atom>
            </Naf>
         </And>
         <Atom>
            <Rel>discount</Rel>
            <Var>customer</Var>
            <Var>product</Var>
            <Ind>5.0 percent</Ind>
          </Atom>
      </Implies>

      <Atom closure="universal">
        <Rel>premium</Rel>
        <Ind>bob</Ind>
      </Atom>

      <Atom closure="universal">
         <Rel>onsale</Rel>
         <Ind>clothes</Ind>
      </Atom>

   </And>
</Assert>

Equality

Equivalence individuals are presented with RuleML tag <Equal></Equal> in OO jDREW BU

For the above example, we define as below:

<Equal>
 <Ind>fatherOFtom</Ind>
 <Ind>bob</Ind>
</Equal> 
<Equal>
 <Ind>fatherOFtom</Ind>
 <Ind>uncleOFmary</Ind>
</Equal>

the coming statements are:

1: discount("uncleOFmary", clothes, "5.0 percent").
1: discount("fatherOFtom", clothes, "5.0 percent").
1: discount("bob", clothes, "5.0 percent").
2: onsale(clothes).
3: premium("uncleOFmary").
3: premium("fatherOFtom").
3: premium("bob").
4: equal("uncleOFmary",uncleOFmary).
4: equal("fatherOFtom",uncleOFmary).
4: equal("bob",uncleOFmary).
4: equal(fatherOFtom,bob).

while another atom is provided as:

<Atom>
 <Rel>special</Rel>
 <Ind>clothes</Ind>
</Atom>

less conclusions we will receive:

1: premium("uncleOFmary").
1: premium("fatherOFtom").
1: premium("bob").
2: equal("uncleOFmary",uncleOFmary).
2: equal("fatherOFtom",uncleOFmary).
2: equal("bob",uncleOFmary).
2: equal(fatherOFtom,bob).
3: onsale(clothes).
4: special(clothes).

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Here is a link to download the extension features of OO jDREW.