It is certain that Jessica is a mouse. We believe that Julius is a rhino. Chances are slight that Emily is a wolf. We believe that if 'Jessica is a mouse' or 'Julius is a rhino' or both then Fred went to the office. It is highly unlikely that if 'Jessica is a mouse and Emily is a wolf' then Daniel grabbed the milk. It is certain that if 'Jessica is a mouse' or 'Emily is a wolf' or both then Lily is a swan.
It is impossible that 'Lily is a swan and Jessica is a mouse'.
It is certain that 'Lily is a swan and Jessica is a mouse'.
It is impossible that 'Lily is a swan 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.
  0.1::factC.
  %hop1
  0.75::factX:-or(factA,factB).
  0.05::factY:-and(factA,factC).
  1.0::factZ:-or(factA,factC).

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

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