Deontic operators might not derive that an atom is deontic

[ovidiomanteiga]

a :- &permitted_implicitly{b}.

Deolingo returns empty answer set even though b is permitted implicitly, but not permitted (explicitly), so a should be derived. But explicitly stating that b is a deontic atom, would make it work.

a :- &permitted_implicitly{b}.
&deontic{b}.

The problem is that the rules deriving the implicit permission, for example, need that the atom is deontic for safety:

&permitted_implicitly{X} :- not &forbidden{X}, &deontic{X}.

But the rules deriving that an atom is deontic only account for those for which there is deontic information derived or assumed (they are obligatory or not, or forbidden or not):

&deontic{X} :- &obligatory{X}.
&deontic{X} :- &deontic{-X}.

This is not a problem for the optimized solver because the rule is rewritten in the body:

a :- not deolingo_forbidden(b).