context: There is a very good chance that Sandra left the football. There is a very good chance that Lily is a lion. It is highly likely that Brian is a rhino. There is a very good chance that if 'Sandra left the football' or 'Brian is a rhino' or both then Greg is white. It is improbable that if either 'Sandra left the football' or 'Brian is a rhino' but not both then Yann is tired. It is probably not the case that if 'Sandra left the football' or 'Brian is a rhino' or both then John went to the office.
hypothesis: There is a very good chance that either 'Lily is a lion' or 'Greg is white' but not both.
valid_hypothesis: It is probably not the case that either 'Lily is a lion' or 'Greg is white' but not both.
invalid_hypothesis: There is a very good chance that either 'Lily is a lion' or 'Greg is white' but not both.
problog: 
    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.
    0.9::factC.
    %hop1
    0.8::factX:-or(factA,factC).
    0.1::factY:-xor(factA,factC).
    0.25::factZ:-or(factA,factC).
  
    %hop2
    conclusion:-xor(factB,factX).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Lily is a lion' or 'Greg is white' but not both.