There is a very good chance that Mary went to the bedroom. There is a better than even chance that Greg is yellow. It is almost certain that Lily is a rhino. It is probably the case that if either 'Mary went to the bedroom' or 'Lily is a rhino' but not both then Brian is a swan. There is a very good chance that if 'Lily is a rhino and Greg is yellow' then Jeff put down the milk. There is little chance that if either 'Lily is a rhino' or 'Mary went to the bedroom' but not both then John discarded the apple.
It is certain that 'Mary went to the bedroom' or 'Lily is a rhino' or both.
It is certain that 'Mary went to the bedroom' or 'Lily is a rhino' or both.
There is almost no chance that 'Mary went to the bedroom' or 'Lily is a rhino' 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
  0.8::factA.
  0.6::factB.
  0.95::factC.
  %hop1
  0.7::factX:-xor(factA,factC).
  0.8::factY:-and(factC,factB).
  0.1::factZ:-xor(factC,factA).

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

  query(conclusion).
  
'Mary went to the bedroom' or 'Lily is a rhino' or both.