It is improbable that John went to the kitchen. We believe that Greg is a lion. It is impossible that Mary left the football. It is improbable that if 'Mary left the football and John went to the kitchen' then Julius is green. It is likely that if 'John went to the kitchen' or 'Mary left the football' or both then Brian is yellow. It is unlikely that if 'Mary left the football and John went to the kitchen' then Bernhard is a frog.
There is almost no chance that 'Greg is a lion' or 'Bernhard is a frog' or both.
We believe that 'Greg is a lion' or 'Bernhard is a frog' or both.
There is almost no chance that 'Greg is a lion' or 'Bernhard is a frog' or both.

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

  %hop2
  conclusion:-or(factB,factZ).

  query(conclusion).
  
'Greg is a lion' or 'Bernhard is a frog' or both.