It is unlikely that Greg is green. It is likely that Mary left the football. It is impossible that Jessica is a mouse. It is probably not the case that if 'Mary left the football' or 'Greg is green' or both then Lily is gray. It is likely that if 'Jessica is a mouse' or 'Mary left the football' or both then John discarded the apple. There is almost no chance that if 'Mary left the football and Jessica is a mouse' then Brian is a frog.
We believe that 'Greg is green' or 'Jessica is a mouse' or both.
It is unlikely that 'Greg is green' or 'Jessica is a mouse' or both.
We believe that 'Greg is green' or 'Jessica is a mouse' 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
  0.2::factA.
  0.7::factB.
  0.0::factC.
  %hop1
  0.25::factX:-or(factB,factA).
  0.7::factY:-or(factC,factB).
  0.02::factZ:-and(factB,factC).

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

  query(conclusion).
  
'Greg is green' or 'Jessica is a mouse' or both.