There is little chance that Sandra left the football. We doubt that Greg is a rhino. It is impossible that John put down the apple. It is improbable that if 'Greg is a rhino and Sandra left the football' then Julius is a lion. It is probably not the case that if 'Greg is a rhino and Sandra left the football' then Lily is yellow. There is a very good chance that if either 'John put down the apple' or 'Sandra left the football' but not both then Mary went to the bedroom.
It is probable that 'John put down the apple' or 'Lily is yellow' or both.
It is impossible that 'John put down the apple' or 'Lily is yellow' or both.
It is probable that 'John put down the apple' or 'Lily is yellow' 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.
  0.2::factB.
  0.0::factC.
  %hop1
  0.1::factX:-and(factB,factA).
  0.25::factY:-and(factB,factA).
  0.8::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'John put down the apple' or 'Lily is yellow' or both.