There is almost no chance that Gertrude is a cat. We believe that Greg is a rhino. It is impossible that John went to the office. It is certain that if 'John went to the office and Greg is a rhino' then Bernhard is green. It is improbable that if 'Greg is a rhino' or 'John went to the office' or both then Julius is white. We believe that if 'Gertrude is a cat and Greg is a rhino' then Mary is in the bathroom.
Chances are about even that 'Gertrude is a cat and Greg is a rhino'.
There is almost no chance that 'Gertrude is a cat and Greg is a rhino'.
Chances are about even that 'Gertrude is a cat and Greg is a rhino'.

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

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

  query(conclusion).
  
'Gertrude is a cat and Greg is a rhino'.