It is improbable that Jessica is a mouse. It is highly likely that Fred went to the garden. It is improbable that Mary got the football. It is highly unlikely that if 'Mary got the football' or 'Jessica is a mouse' or both then Bernhard is green. It is highly unlikely that if 'Mary got the football and Fred went to the garden' then Daniel left the apple. Chances are slight that if 'Fred went to the garden' or 'Jessica is a mouse' or both then Julius is white.
It is unlikely that 'Jessica is a mouse' or 'Mary got the football' or both.
It is unlikely that 'Jessica is a mouse' or 'Mary got the football' or both.
It is certain that 'Jessica is a mouse' or 'Mary got the football' 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.
  0.9::factB.
  0.1::factC.
  %hop1
  0.05::factX:-or(factC,factA).
  0.05::factY:-and(factC,factB).
  0.1::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Jessica is a mouse' or 'Mary got the football' or both.