It is certain that Greg is a frog. We believe that Brian is white. It is impossible that Jessica is a mouse. It is certain that if 'Jessica is a mouse and Brian is white' then Fred is in the school. There is little chance that if 'Greg is a frog and Jessica is a mouse' then Bernhard is a swan. It is probable that if 'Greg is a frog' or 'Jessica is a mouse' or both then Lily is green.
It is probable that 'Lily is green and Jessica is a mouse'.
It is impossible that 'Lily is green and Jessica is a mouse'.
It is probable that 'Lily is green and Jessica is a mouse'.

  and(A,B) :- A,B.
  or(A,B) :- A;B.
  nand(A,B) :- not(and(A,B)).
  nor(A,B) :- not(or(A,B)).
  xor(A,B) :- or(A,B), nand(A,B).

  %hop0
  1.0::factA.
  0.75::factB.
  0.0::factC.
  %hop1
  1.0::factX:-and(factC,factB).
  0.1::factY:-and(factA,factC).
  0.7::factZ:-or(factA,factC).

  %hop2
  conclusion:-and(factZ,factC).

  query(conclusion).
  
'Lily is green and Jessica is a mouse'.