Chances are about even that Mary left the football. There is a better than even chance that Lily is a lion. We doubt that John went to the hallway. It is highly unlikely that if 'Lily is a lion and John went to the hallway' then Jessica is a cat. It is improbable that if 'John went to the hallway' or 'Lily is a lion' or both then Daniel took the football. It is improbable that if 'Mary left the football and Lily is a lion' then Greg is a rhino.
It is probably the case that 'Greg is a rhino' or 'Daniel took the football' or both.
It is improbable that 'Greg is a rhino' or 'Daniel took the football' or both.
It is probably the case that 'Greg is a rhino' or 'Daniel took the football' 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
  0.5::factA.
  0.6::factB.
  0.2::factC.
  %hop1
  0.05::factX:-and(factB,factC).
  0.1::factY:-or(factC,factB).
  0.1::factZ:-and(factA,factB).

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

  query(conclusion).
  
'Greg is a rhino' or 'Daniel took the football' or both.