Re: [foaf-dev] mbox_sha1sum describes only email

>> Note that the foaf:sha1sum solution I am proposing does not take the
>> checksum of the file referenced by the
>> URL. Your fp:checksum has a domain of foaf:Document. The one I am
>> proposing here, perhaps better named
>>
>> xxx:uriChecksum would have a domain of owl:Thing, ie, anything that
>> can be named.
>>
>> For example it makes no sense to give a checksum of a person or
>> mailbox.
>>
>> [] a foaf:Person;
>>   xxx:uriChecksum "hjsdfsjhfskjhdfskj";
>>   foaf:mbox [ xxx:uriChecksum "ssdfsfsfskjlkjl;ksdf1234" ] .
>>
>> Now how useful this really is is up for debate. But it would give  
>> us a
>> generalisation of the
>> foaf:mbox_sha1sum relation .
>>
>> Henry
>
>
> The problem with doing it like this, is it messes up the range for  
> foaf:mbox
> and would cause problems for any software hoping to find an actual  
> address
> as it's object. What we need, instead, is something closer to  
> reification
> syntax.:
>
> [] a foaf:person;
>    xxx:hash [
>        rdfs:subject "foaf:mbox";
>        xxx:uriChecksum "ssdfsfsfskjlkjl;ksdf1234"]
>    xxx:hash [
>        rdfs:subject "foaf:firstName";
>        xxx:literalChecksum "hjsdfsjhfskjhdfskj"] .
>
> This would allow you to describe any triple by not giving the value  
> of it's
> object, but by giving the hash of that object. (either uri or literal)
>
> "This person has a mailbox. I don't know what it is, but it's hash is
> this..."

That is exactly what the proposed xxx:uriChecksum relation I am  
proposing would be.

[] a foaf:Person
    foaf:mbox [ xxx:uriHash "hjsdfsjhfskjhdfskj" ] .

this is saying there is a person who has a foaf mbox, that is unknown,  
and that the uri of the mbox has the given hash sum  
"hjsdfsjhfskjhdfskj" . To make this clearer, here is the same  
expressed with bnodes:

_:p1 a foaf:Person;
    foaf:mbox _:b .

_:b xxx:uriHash "hjsdfsjhfskjhdfskj" .

This seems simpler than what you are proposing above.

>
>
> I don't have the specifics quite right, but hopefully you can see  
> the idea
> I'm trying to express.
>