Small change to SSN ontology

Dear all,

We are currently reviewing a pull request (https://github.com/w3c/sdw/pull/924) that makes a small change to the normative part of the SSN document (http://w3c.github.io/sdw/ssn/), i.e. it proposes to remove the following two axioms from the SSN ontology:

ssn:hasProperty a owl:InverseFunctionalProperty ;
ssn:isPropertyOf a owl:FunctionalProperty ;

This removal of the axiom has become necessary as we had inquiries in the public review to allow generic modelling of properties, see also: https://www.w3.org/2015/spatial/wiki/Generic_vs_Specific_Modeling. This axiom could lead to entailments that two Features of Interest are equivalent (even though they may not) through an equivalence entailment of their properties (as each individual of a Property of one Observation would be equivalent through the functional property axiom).

We are sending this email to the list to avoid the need to another vote on the SSN document for it to become rec-track. Since this change represents a relaxing of the semantics in SSN, we do not expect any objections, but please let us know if you disagree with that change.

Kind regards,
Armin