It is unlikely that Gertrude is a cat. It is impossible that Julius is a lion. It is impossible that Sandra took the football. It is highly likely that if 'Gertrude is a cat and Julius is a lion' then Lily is a rhino. It is probably not the case that if either 'Julius is a lion' or 'Gertrude is a cat' but not both then Greg is green. It is probably the case that if either 'Julius is a lion' or 'Sandra took the football' but not both then Brian is yellow.
It is impossible that 'Greg is green and Lily is a rhino'.
It is impossible that 'Greg is green and Lily is a rhino'.
There is a better than even chance that 'Greg is green and Lily 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
  0.2::factA.
  0.0::factB.
  0.0::factC.
  %hop1
  0.9::factX:-and(factA,factB).
  0.25::factY:-xor(factB,factA).
  0.7::factZ:-xor(factB,factC).

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

  query(conclusion).
  
'Greg is green and Lily is a rhino'.