Chances are about even that John put down the apple. It is unlikely that Bernhard is yellow. It is unlikely that Brian is a rhino. It is highly likely that if either 'Bernhard is yellow' or 'John put down the apple' but not both then Lily is a frog. There is a very good chance that if 'Brian is a rhino' or 'John put down the apple' or both then Mary left the football. We doubt that if 'John put down the apple and Brian is a rhino' then Emily is a sheep.
It is impossible that 'Bernhard is yellow and Emily is a sheep'.
It is impossible that 'Bernhard is yellow and Emily is a sheep'.
It is probable that 'Bernhard is yellow and Emily is a sheep'.

  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.
  0.2::factB.
  0.2::factC.
  %hop1
  0.9::factX:-xor(factB,factA).
  0.8::factY:-or(factC,factA).
  0.2::factZ:-and(factA,factC).

  %hop2
  conclusion:-and(factB,factZ).

  query(conclusion).
  
'Bernhard is yellow and Emily is a sheep'.