It is highly likely that Gertrude is a cat. There is a better than even chance that Brian is white. It is highly unlikely that Lily is green. There is a very good chance that if either 'Gertrude is a cat' or 'Brian is white' but not both then Daniel took the football. It is highly unlikely that if 'Brian is white and Gertrude is a cat' then Mary went to the hallway. It is probably not the case that if either 'Lily is green' or 'Brian is white' but not both then John put down the apple.
It is highly unlikely that 'Lily is green and Gertrude is a cat'.
It is highly unlikely that 'Lily is green and Gertrude is a cat'.
It is likely that 'Lily is green and Gertrude is a cat'.

  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
  0.9::factA.
  0.6::factB.
  0.05::factC.
  %hop1
  0.8::factX:-xor(factA,factB).
  0.05::factY:-and(factB,factA).
  0.25::factZ:-xor(factC,factB).

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

  query(conclusion).
  
'Lily is green and Gertrude is a cat'.