Understanding n-ary data predicates

Hi!

I haven't attended the last telco, where n-ary predicates were discussed. I 
would like to catch up on this topic. However, from looking into the proposal 
[1], I do not even understand the basic idea. :-(

The use-cases document [2] provides the following example:

  "For humans, the systolic blood pressure is always
  greater or equal than the diastolic blood pressure."

I speculated that the idea was to have a new "GreaterOrEqual" property 
restriction, which is applied on two properties:

  SubClassOf( Human
              GreaterOrEqual(systolicBloodPressure diastolicBloodPressure) ))

And the value ranges for these two properties can be specified by additional 
AllValues restrictions.

But it doesn't look to me that the actual proposal follows this approach. So, 
can anyone please demonstrate the actual approach for the above 
"systolic/diastolic" example?

Thanks in advance,
Michael

[1] Proposal: <http://www.w3.org/2007/OWL/wiki/N-ary_Data_predicate_proposal>
[2] Use-Cases: <http://www.w3.org/2007/OWL/wiki/N-ary_Data_predicate_use_case>