- From: Paolo Missier <Paolo.Missier@ncl.ac.uk>
- Date: Mon, 18 Jul 2011 18:50:01 +0100
- To: public-prov-wg@w3.org
- Message-ID: <4E247249.7000305@ncl.ac.uk>
Reza, it's worth trying to make progress on this as we are in the process of editing a document draft. I can see the dilemma: - the less you specify in the model, the more you risk incompatibilities as different implementations make their own choices to fill the gaps; - but by adding specific extensions to the top-level concepts in the model, you risk to make those choices arbitrary. But in this specific instance, I believe that "trusted" is one specific qualification of "Agent" that does not belong to the model, rather it belongs to applications that use the model (i.e., to /assess some measure of trust/). But I see your need for a "placeholder" where I can assert something about how trust for Agents. This is fine: let Trusted not be a sub-class of Agent, but let "Trust properties" can be properties of Agent. Would that be a problem? Any application that knows about trust would fill in into those properties. To repeat my proposal, I see Agent as a Role that any first-class entity in the model can take on when it is involved in relations that concern activities. The general lesson I see from this thread is that we urgently need to discuss how principled extension mechanisms ("profiles") make it into our proposal. atb -Paolo On 7/14/11 10:06 PM, Reza B'Far wrote: > Ok. At this point, I'm resigning to the fact that I'm in the minority. However, just look at HTML as a data point: > > They could have made <p></p> and <div></div> tags into the same generic tag with an attribute (or attributes). I would argue that > they made the right decision(s) in the strong types they created, though not all were perfect decisions (e.g. <blink>). That > "strongly encouraged" all the implementers of browsers to define rendering of a paragraph in a specific way (and different from > <div) which is more loose). The core issue is compatibility. If you make something generic and provide only soft guidelines for > extensions, you end up with compatibility issues when product implementers build their products because they will do whatever they > can within the specification to differentiate their products. Ignoring that fact risks success of a standard once implemented. > > But, I end with my original statement that I'll drop the topic. > > On 7/14/11 1:57 PM, Daniel Garijo wrote: >> Hi Reza, all, >> I agree with you in that subtyping is very important from an implementer persepctive. >> However I think that the model discussed in the model TF is supposed to be generic, >> and once we have it, the test cases TF can develop some profiles subtyping all the >> generic concepts, showing examples of how it would be extended in different domains. >> Thus, developers could use these profiles as reference for other extensions. >> Best, >> Daniel >> >> 2011/7/14 Reza B'Far <reza.bfar@oracle.com <mailto:reza.bfar@oracle.com>> >> >> I agree that it's the right thing to do to keep trust definition out of the scope of WG. However, if the group is saying >> that defining touch points to the tangent layers, per your own references, is also out of scope, then I warn that there is a >> fundamental problem for product implementers. If you want to exclude all aspects of trust including any think like the >> ability to embed something else via a URI or something like that to a trust mechanism, then you'll have compatibility issues >> from different product vendors. If you want to do that knowingly, it's fine and I'll drop the thread, but if you disagree >> and think that exclusion of trust doesn't cause fundamental incompatibility, we can continue thread and I can provide more >> details on why this is the case. >> >> So, my point from the beginning is that without subtyping, things are too generic to be able to import and export things >> about entities between different systems. And I believe a primary use-case for usage of the model is import/export between >> different implementations. >>
Received on Monday, 18 July 2011 17:50:35 UTC