INPUT TEXT:
If a message X is not provably not important then X is important.
Message13 is a message that is not important.
Message36 is a message.
Message74 is a message that is important.

RULES:
-group([property(named('Message13'),important,pos)]).
group([property(A,important,pos)]) <- [object(A,message,countable,na,eq,1), ~ -group([property(A,important,pos)])].
group([property(named('Message74'),important,pos)]).
object(named('Message13'),'Message13',named,na,eq,1).
object(named('Message13'),message,countable,na,eq,1).
object(named('Message36'),'Message36',named,na,eq,1).
object(named('Message36'),message,countable,na,eq,1).
object(named('Message74'),'Message74',named,na,eq,1).
object(named('Message74'),message,countable,na,eq,1).

SIMPLE RULES:
-important(named('Message13')).
important(A) <- [message(A), ~ -important(A)].
important(named('Message74')).
message(named('Message13')).
message(named('Message36')).
message(named('Message74')).

ANSWERSET #1:
object(named('Message13'),'Message13',named,na,eq,1).
object(named('Message13'),message,countable,na,eq,1).
object(named('Message36'),'Message36',named,na,eq,1).
object(named('Message36'),message,countable,na,eq,1).
object(named('Message74'),'Message74',named,na,eq,1).
object(named('Message74'),message,countable,na,eq,1).
group([property(named('Message36'),important,pos)]).
group([property(named('Message74'),important,pos)]).
-group([property(named('Message13'),important,pos)]).

ANSWERTEXT #1:
Message74 is important.
Message36 is important.
Message74 is a message.
Message36 is a message.
Message13 is a message.
It is false that Message13 is important.