In the following docs: https://jena.apache.org/documentation/inference/
The arithmetic builtins are described as such: "Note that these do not run backwards, if in sum a and c are bound and b is unbound then the test will fail rather than bind b to (c-a). This could be fixed." This is repeated in the source code for said functions. https://github.com/apache/jena/blob/master/jena-core/src/main/java/org/apache/jena/reasoner/rulesys/builtins/Sum.java in that case at line 78. My question is: is the only reason this does not work because the Builtin doesn't handle it, or because the engine wouldn't be able to work correctly if the Builtin was fixed? -- Paul Houle paul.ho...@ontology2.com
