N3 loops , validation and cutoffs

Hi


I'm learning about N3 for a PhD project on decentralized scholarly communication I joined this year (at IDLab in Ghent). In this project we want to use N3 as rule books published online that get executed by browsers, intelligent agents, servers to start some business logic.


There are some things in N3 where I need a bit more insight. One is the processing of N3 requires some kind of recursion (due to the fact that formulas can be in any order, the result of a formula can be the input of the same formula). These recursions can lead to infinite loops as in this (pathetic) example:


@prefix : <urn:x:>.

:Hank :loves :Pizza.

{ ?X :loves ?Y . } => { [] :loves ?X . } .


 I know that in EYE (and probably also in CWM) these loops can be prevented by introducing a cutoff in the reasoning engine (asking the engine to stop processing formulas at some point).

Is it possible add extra formulas that can prevent that these cutoffs are needed? I know I'm asking for a solution to the halting problem, but just to be sure I don't miss anything obvious. When receiving N3 documents from third parties, my engine don't know what cutoffs or optimizations are required.


I am also curious why CWM and EYE give different answers for this (pathetic) example:


@prefix : <urn:x:>.

:Hank :loves :Pizza.

{ ?X :loves ?Y . } => { [] :loves ?Y . } .


CWM:

[      <urn:x:loves> <urn:x:Pizza> ].


EYE:


{no new quads produced}


BR

Patrick