Dear Stanbol friends, as you know there are some issues related to three LGPL dependencies in the code.
Briefly, this is the status: * OWLApi -> solved, the latest code in SVN is dual licensed * OWLLink -> going to be solved, we have informal guarantees it will be delivered dual licensed, as OWLApi * HermiT -> this is still a problem, and is the main reason of this e-mail The stanbol/reasoners module offers some rest based reasoning services. They come with a built-in reasoner (HermiT[1], currently), or a binding to an OWL Link[2, 3] client. HermiT cannot be used right now. It is LGPL v3 licensed and includes another LGPL dependency (JAutomata). Hermit team cannot devolve time to fix this for licensing needs. We can see if this can be overcomed by contacting the JAutomata maintainers but I would not see it as a solution for the near future. OWLLink will be released in a dual license fashion soon, this means that we will provide extendibility of reasoners through it (users can then setup an OWLLink server with HermiT, Pellet, for instance). But we need to provide to the Stanbol users some base reasoning capabilities embedded in the default distribution. Actually, it seems that do not exists a OWL2 reasoner with a license compatible with Apache criteria. The Jena project (now incubating in Apache[4] ) incudes a rule based reasoner, which has also a default configuration which supports a subset of OWL axioms (known as OWL lite, similar to OWL EL profile[5]). If anybody wants can have more details about OWL profiles here[6] - in two words is a way of restricting the number of statements supported by the language to have more efficiency. What is interesting is that Stanbol comes with a rule system (stanbol/rules) which is currently used for graph refactoring operations, and can therefore adapt to work with the Jena reasoner. We would have: * A default OWL Lite reasoner as built-in DL reasoner. * A generic rule based reasoner which could be fed by stanbol recipes (in the future we could define different instances based on different Stanbol recipes, or we can study/test more 'profiles', for specific tasks) We would loose: * Support for some statements of OWL2 in the default built in reasoner, for instance complex Class expressions in axiom subjects. Corrections/extensions of what I'm writing are welcome, of course. I propose to concentrate the work, for the moment, to these tasks: + Add Jena rule based reasoner as a new separate inference module inside the reasoners package; + Implement the Reasoners OWLApi interface to adapt to Jena rule based inference engine with OWL lite profile; + Remove HermiT fro within the reasoners module What do you think? Other ideas? Enrico [1] http://hermit-reasoner.com/ [2] http://www.owllink.org/ [3] http://owllink-owlapi.sourceforge.net/ [4] http://incubator.apache.org/jena/ [5] http://jena.sourceforge.net/inference/ [6] http://www.w3.org/TR/owl2-profiles/ -- Enrico Daga -- http://www.enridaga.net skype: enri-pan
