re: Expression Question about DL

Thank you very much Mr. Walker.

 

I’ve visited the page

http://www.reengineeringllc.com/demo_agents/RDFQueryLangComparison1.agent,

But I didn’t think my question is answered.

The agent was designed carefully to avoid such expression in my question.

 

My question can be shown as a graph below:



Paper is written by an author.

Presentation is made by an author.

Paper is presented at a Presentation.

Here is a cycle!

 

I want to restrict that the paper which is presented at a presentation,  
which is presented by an author, which is exactly this paper’s author.

In other word, Let set S1, S2, R1 is a relation of (S1,S2), R2 is a relation
of (S2,S3),

and R3 is of (S1,S3), if s1,s2,s3 belong to S1, S2 S3 respectively, 

and R1(s1,s2), R2(s2,s3),R3(s1,s3’), then I want to restrict s3=s3’.

The question here is that not the whole combination result R1○R2=R3,

but the individual combination should be equal.

 

Does such expression is permitted in DL?

 

 

Appreciates any comment! 

                                                               Cai shubin

 

  _____  

发件人: Adrian Walker [mailto:adrianw@snet.net] 
发送时间: 2005年10月16日 3:05
收件人: cai
抄送: semantic-web@w3c.org
主题: Re: Expression Question about DL

 

Hi  Cai --

What you would like to do, (described in your note below), would be a
straightforward extension of 

   http://www.reengineeringllc.com/demo_agents/RDFQueryLangComparison1.agent

which is also about papers an their authors.

If you'd like to try this route, please let me know if there are questions.

                                -- Adrian





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At 11:47 AM 10/15/2005 +0800, you wrote:

Dear Sir or Madam:

     I have difficulty in writing such assertions in Description Logic.

At first, I have three assertions,

1: Every Presentation is made by a Person.  

2: Every Paper is introduced at a Presentation.

3: Every Paper is (mainly) written by a Person.

I can write them in DL as below:

image00123.jpg

But I can not write an assertion to state that 

4: Every Paper is introduced at a Presentation by the paper's writer,

 

     Sincerely appreciate any suggestion!

                                 

                                                        Cai Shubin