There is a very good chance that Brian is a rhino. There is a very good chance that Gertrude is a cat. It is certain that Jason is tired. We believe that if 'Gertrude is a cat and Brian is a rhino' then Bernhard is a swan. It is highly likely that if 'Brian is a rhino' or 'Gertrude is a cat' or both then Mary got the apple. It is likely that if 'Gertrude is a cat' or 'Brian is a rhino' or both then Lily is yellow.
It is certain that 'Gertrude is a cat' or 'Jason is tired' or both.
It is certain that 'Gertrude is a cat' or 'Jason is tired' or both.
It is highly unlikely that 'Gertrude is a cat' or 'Jason is tired' 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.
  0.8::factB.
  1.0::factC.
  %hop1
  0.75::factX:-and(factB,factA).
  0.9::factY:-or(factA,factB).
  0.7::factZ:-or(factB,factA).

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

  query(conclusion).
  
'Gertrude is a cat' or 'Jason is tired' or both.