There is a very good chance that Greg is yellow. We believe that Bernhard is a rhino. It is almost certain that John put down the apple. It is likely that if 'Greg is yellow and John put down the apple' then Brian is yellow. There is a better than even chance that if either 'Bernhard is a rhino' or 'John put down the apple' but not both then Mary went to the office. There is a better than even chance that if 'Bernhard is a rhino' or 'Greg is yellow' or both then Emily is a mouse.
It is impossible that 'Emily is a mouse' or 'Brian is yellow' or both.
There is a very good chance that 'Emily is a mouse' or 'Brian is yellow' or both.
It is impossible that 'Emily is a mouse' or 'Brian 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
  0.8::factA.
  0.75::factB.
  0.95::factC.
  %hop1
  0.7::factX:-and(factA,factC).
  0.6::factY:-xor(factB,factC).
  0.6::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Emily is a mouse' or 'Brian is yellow' or both.