Bobbin, I changed the title for this topic. Before discussing any issues of modeling anything, it's important to start with an example. I suggest that we make this topic an Ontolog project: You send us a specification of whatever holonic structures you would like to represent. Instead of using OWL, I suggest that we use Controlled English for two subsets of Common Logic: (1) A type hierarchy specified by Aristotle's syllogisms, and (2) Full first-order logic for the constraints. Then anybody who prefers OWL can map the controlled English to OWL (if they can). If they can't, that would show why you had difficulty in mapping your problems to OWL. I also recommend controlled natural languages (CNLs) for any other languages anybody would prefer. But we can stick with CE for the Ontolog discussion. For a tutorial on Controlled English (CE) and its mapping to logic, see Patterns of Logic and Ontology: https://jfsowa.com/talks/patolog1.pdf . Those are slides that I used for the first day of a 5-day short course that I taught in 2019. Patolog1 should be sufficient for an intro to CE. If anybody needs more examples, see Patolog2, 3, 4, or 5. And by the way, these slides are closely related to my book Knowledge Representation, which was published in 2000, but they were updated with another 20 years of publications and collaboration with Arun Majumdar and other colleagues in our VivoMind company. I discuss some VivoMind examples in various slides, especially Patolog4 and 5. If you still have any of the notes that Pat Hayes sent you, I suggest that you package all of them in one PDF together with whatever holonic specifications you are working on. Then send them to us as just one file. It's better to keep it all together instead of putting them in a collection of a lot of little files. And by the way, if anybody has trouble with CE, just look at the examples and make your best guess. That is how we designed the controlled English for VivoMind and for our new Permion company. It's very forgiving. It never says "Error". It just comes back with an English echo and the question "Is this what you mean?" If not, you can revise it until you're happy with the echo. My personal opinion about the SW stack: It's legacy software that nobody should ever need to learn or use. All knowledge representations should be specified in CNLs supplemented with diagrams. The only people who would have to use other notations should be those who spent years in designing and/or learning them. Today we have the technology for supporting that policy. John ---------------------------------------- From: "Bobbin Teegarden" <teegs(a)earthlink.net> John, a question re your suggested hierarchies below: I have been frustrated by owl’s lack of composition. Even UML has composition (and aggregation, a special case of composition). I have been working with holons and holonic structures (for contexts and such) and need compositions. Pat Hayes once told me that there were lots of composition/mereology ontologies out there, just pick one. Frustrating. Your suggestions solicited. How would I model complex holonic structures on OWL? Thanks, Bobbin