Chances are about even that Mary left the football. It is probable that Gertrude is a wolf. Chances are about even that Antoine is thirsty. It is improbable that if 'Mary left the football and Gertrude is a wolf' then Jessica is a cat. There is a very good chance that if 'Antoine is thirsty and Gertrude is a wolf' then Lily is a rhino. It is probably not the case that if 'Antoine is thirsty' or 'Mary left the football' or both then Brian is a frog.
Chances are about even that 'Lily is a rhino' or 'Antoine is thirsty' or both.
Chances are about even that 'Lily is a rhino' or 'Antoine is thirsty' or both.
It is certain that 'Lily is a rhino' or 'Antoine is thirsty' 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
  0.5::factA.
  0.7::factB.
  0.5::factC.
  %hop1
  0.1::factX:-and(factA,factB).
  0.8::factY:-and(factC,factB).
  0.25::factZ:-or(factC,factA).

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

  query(conclusion).
  
'Lily is a rhino' or 'Antoine is thirsty' or both.