context: There is a better than even chance that Yann is tired. It is certain that Mary dropped the apple. It is probable that John got the milk. It is unlikely that if 'Yann is tired' or 'Mary dropped the apple' or both then Fred went to the garden. It is unlikely that if 'Yann is tired and Mary dropped the apple' then Jason is bored. There is little chance that if either 'John got the milk' or 'Yann is tired' but not both then Brian is a frog.
hypothesis: Chances are about even that 'Yann is tired and John got the milk'.
valid_hypothesis: Chances are about even that 'Yann is tired and John got the milk'.
invalid_hypothesis: There is almost no chance that 'Yann is tired and John got the milk'.
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
    0.6::factA.
    1.0::factB.
    0.7::factC.
    %hop1
    0.2::factX:-or(factA,factB).
    0.2::factY:-and(factA,factB).
    0.1::factZ:-xor(factC,factA).
  
    %hop2
    conclusion:-and(factA,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Yann is tired and John got the milk'.