Dear Hilmar,
Thanks for this insight. I have to admit to no prior experience of mereology, but the desire to find a solution to how to semantically encode morphological observations in a fashion which many can agree upon prods me to reply. Sorry if I am way in out of my depth and it shows!
We can also employ the OBO relational ontology (ro) to indicate that a fruit is ro:part_of the particular space-time Occurrence of an Individual (this might require a bit more discussion!).
I don't think you can do that actually, given the definition of the relation [1]. I.e., to me the definition sounds like it is true meristic parthood that is meant here (and for which it is applied in the uses that I have seen). The fruit has some role in Occurrence, but isn't a part of it in the sense of meristics, don't you think?
If we consider the occurrence to be the intersection of the individual with an (observation) event in a particular space and time (e.g., tzxy0), I think a fruit_txyz0 is indeed part of plant_txyz0, fulfilling the ro:part_of definition of:
``For continuants: C part_of C' if and only if: given any c that instantiates C at a time t, there is some c' such that c' instantiates C' at time t, and c *part_of* c' at t.''
The alternative to making the fruit a part of the dwc:Occurrence is to make it a part_of the sernec:Individual, which could then be observed via the OBOE terms, at a particular place and time (although strangely there seems to be no date/time observation terms in OBOE). This second alternative would be less satisfying though, given that dwc:Occurrences have already been specified to include Observations. Maybe using dcterms:isPartOf would be OK, since it is less precisely defined?
Also, the quantification doesn't match: If A ro:part_of B, then all instances of A part_of some instance of B. Obviously, there are some fruits that haven't been recorded in an occurrence.
I agree with this, but this must surely be a generic issue within the whole OBO/organismal annotation world - often a phenotype must be recorded for c, which is part_of c', without having considered every instance of C.
This is clearly an issue to take up with the TDWG Observations WG, and I'll post to the new post-Wood's Hole list shortly. If any of you have any suggestions for how to progress with this, I'd appreciate them.
Best,
Cam