[tannhaeuser]

With compliments to your prof ;), interest in Prolog just now is recovering from a year-long focus on W3C's RDF/SPARQL. TBL surely had an itch to scratch with regards to logical knowledge representation dating back even longer than the web [1]. But Prolog has broader applicability not only in logical/knowledge graph querying, but also in solving all kinds of discrete combinatorical optimization problems. Or, as the Quantum Prolog site [2] puts it, "planning, optimization, diagnostics, and complex configuration." The site demos logistics optimization (in-browser demo) and reports initial optimization (parallelization) of Inductive Logic Programming and other ML tasks for partially auto-generating Prolog code from existing solutions.

Edit: ... and on performance vs SWI Prolog, too

[1]: https://en.wikipedia.org/wiki/ENQUIRE

[2]: https://quantumprolog.sgml.io

[PaulHoule]

The problem w/ OWL is that everybody wants to work with first-order logic + math, but Gödel proved it isn't decidable.

For instance if I wanted to express financial regulations or business rules inside a bank or other business I'd need to use math: for instance to express the conditions for reserve requirements or approving a loan.

OWL is best thought of as a set of templates for generating first-order logic rules that are decidable and also (in theory) quick to evaluate with the Tableau algorithm.

In certain domains you might tolerate tools that are imperfect, like it isn't fair to expect a SMT solver to figure out this one

   x^N + y^N = z^N

where x,y,z and N are all positive integers with N>2. For that one it would try to find solutions and probably time out. For some similar problems (a different polynomial) it might give you an answer.

OWL doesn't want to go there which is a big reason people say "Nein Danke!"

[kstrauser]

> Gödel proved it isn't decidable.

He did no such thing. He proved undecidable problems exist in any system powerful enough to be useful. That doesn’t make those systems useless, though.

[PaulHoule]

The trouble is the creators of OWL wanted to have performance and reliability bounds. That is, they want to make systems that act like more like a conventional database server than an SMT solver.

I think they could have made a more expressive standard and something like that might have had more appeal to people but been less consistent in terms of performance.