There is a very good chance that Greg is a lion. It is almost certain that Emily is a wolf. We doubt that Jeff moved to the garden. It is probably not the case that if 'Greg is a lion' or 'Jeff moved to the garden' or both then Brian is a frog. Chances are about even that if 'Jeff moved to the garden and Greg is a lion' then Mary left the football. There is a better than even chance that if 'Emily is a wolf' or 'Jeff moved to the garden' or both then John went to the bedroom.
There is almost no chance that 'Brian is a frog' or 'Emily is a wolf' or both.
It is almost certain that 'Brian is a frog' or 'Emily is a wolf' or both.
There is almost no chance that 'Brian is a frog' or 'Emily is a wolf' 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.
  0.95::factB.
  0.2::factC.
  %hop1
  0.25::factX:-or(factA,factC).
  0.5::factY:-and(factC,factA).
  0.6::factZ:-or(factB,factC).

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

  query(conclusion).
  
'Brian is a frog' or 'Emily is a wolf' or both.