context: It is highly likely that Yann is hungry. There is a very good chance that Emily is a sheep. There is a better than even chance that Bernhard is gray. We believe that if 'Emily is a sheep' or 'Bernhard is gray' or both then John went to the kitchen. We doubt that if either 'Bernhard is gray' or 'Emily is a sheep' but not both then Lily is green. It is almost certain that if either 'Bernhard is gray' or 'Yann is hungry' but not both then Mary left the football.
hypothesis: It is probably not the case that either 'Lily is green' or 'Mary left the football' but not both.
valid_hypothesis: It is probably not the case that either 'Lily is green' or 'Mary left the football' but not both.
invalid_hypothesis: We believe that either 'Lily is green' or 'Mary left the football' 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
    0.9::factA.
    0.8::factB.
    0.6::factC.
    %hop1
    0.75::factX:-or(factB,factC).
    0.2::factY:-xor(factC,factB).
    0.95::factZ:-xor(factC,factA).
  
    %hop2
    conclusion:-xor(factY,factZ).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Lily is green' or 'Mary left the football' but not both.