[sc34wg3] New syntax for (binary) associations

[Dmitry]

On 31-Jan-08, at 1:51 PM, Steve Pepper wrote:

> I want to make sure I understand this proposal correctly:
>
> * Lars Heuer
> |
> | > The idea to create binary assocs with predefined role types
> | > (subject, object) is sexy, but I wonder if this is the right
> | > thing for CTM.
>
> Question: Would every association of every type that uses this
> proposed syntax end up with the two predefined role types
> 'subject' and 'object'? In other words:
>
>    born-in( subject puccini, object lucca )
>    composed-by( subject tosca, object puccini )
>    located-in( subject lucca, object tuscany )
>    etc.
>

Additional idea about standard roles "tm:subject" and "tm:object" :

With standard roles and nested topics we will be able to say  
something like this:

john
    isa o:Employee;
    o:works-for   [ The-Beatles  isa o:Employer]
.

It is not the same as saying

o:works-for(o:employee: john, o:employer: The-Beatles)

but I think it somehow represents the "original need" for   
specialized  roles.

It also simplifies defining constraints and using external inference  
engines if someone wants to use them.

o:Employee
     tc:plays_role_in  [
          tc:association_type o:works_for;
          tc:card_min 1;
          tc:range o:Organization
    ]

o:Employer
     tc:plays_role_in  [
          tc:association_type o:works_for;
          tc:role tm:object;
          tc:card_min 1;
          tc:range o:Person
    ]


Dmitry