distributed-ontology Blocks_with_Circumscription
logic CommonLogic

ontology Blocks = 
  %% FIXED PART 
    (and (Block B1) (Block B2) (not (= B1 B2))) 
        %% B1 and B2 are different blocks
then
  %% CIRCUMSCRIBED PART
  minimize {
    (Ab B1) %% B1 is abnormal
  }
then
  %% VARYING PART
  (forall (x) (if (and (Block x) (not (Ab x))) (Ontable x)))
        %% Normally, a block is on the table
then %implied
  (Ontable B2)  %% B2 is on the table
end

ontology Blocks_Alternative =
  (and (Block B1) (Block B2) (not (= B1 B2)))
          %% B1 and B2 are different blocks
  (Ab B1) %% B1 is abnormal
  (forall (x) (if (and (Block x) (not (Ab x))) (Ontable x)))
          %% Normally, a block is on the table
  minimize Ab %% var Ontable
then %implies
  (Ontable B2)  %% B2 is on the table
end