Euler is an inference engine supporting logic based proofs. It is a backward-chaining reasoner enhanced with Euler path detection. The Euler path detection is roughly "don't step in your own steps" to avoid vicious circles so to speak and in that respect there is a similarity with what Leonhard Euler discovered in 1736 for the Königsberg Bridge Problem .
The current reasoning engine is EYE . The reasoning that EYE is performing is grounded in FOL (First Order Logic). Keeping a language less powerful than FOL is quite reasonable within an application, but not for the Web .
Via N3  it is interoperable with W3C Cwm .
Been using this for > 2 years. Excellent engine! :)
very good project, thanks!