There is a very good chance that Bernhard is a lion. It is highly likely that Lily is green. It is probably the case that Mary took the football. It is highly likely that if either 'Lily is green' or 'Mary took the football' but not both then Fred went to the garden. There is little chance that if either 'Lily is green' or 'Bernhard is a lion' but not both then Brian is a frog. We believe that if 'Mary took the football and Bernhard is a lion' then Greg is yellow.
There is little chance that 'Brian is a frog' or 'Mary took the football' or both.
It is probable that 'Brian is a frog' or 'Mary took the football' or both.
There is little chance that 'Brian is a frog' or 'Mary took 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
  0.8::factA.
  0.9::factB.
  0.7::factC.
  %hop1
  0.9::factX:-xor(factB,factC).
  0.1::factY:-xor(factB,factA).
  0.75::factZ:-and(factC,factA).

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

  query(conclusion).
  
'Brian is a frog' or 'Mary took the football' or both.