It is almost certain that Jessica is a cat. It is almost certain that Greg is a lion. Chances are slight that Bernhard is a swan. There is little chance that if 'Jessica is a cat' or 'Greg is a lion' or both then Gertrude is a mouse. It is likely that if 'Greg is a lion and Jessica is a cat' then Jason is tired. It is unlikely that if 'Greg is a lion and Bernhard is a swan' then Lily is a frog.
There is a better than even chance that 'Greg is a lion and Jason is tired'.
There is a better than even chance that 'Greg is a lion and Jason is tired'.
There is little chance that 'Greg is a lion and Jason is tired'.

  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
  0.95::factA.
  0.95::factB.
  0.1::factC.
  %hop1
  0.1::factX:-or(factA,factB).
  0.7::factY:-and(factB,factA).
  0.2::factZ:-and(factB,factC).

  %hop2
  conclusion:-and(factB,factY).

  query(conclusion).
  
'Greg is a lion and Jason is tired'.