context: There is little chance that Julius is yellow. It is probably not the case that Greg is a rhino. It is probably not the case that Mary went to the bedroom. There is almost no chance that if 'Julius is yellow' or 'Greg is a rhino' or both then John discarded the apple. It is probably not the case that if 'Mary went to the bedroom' or 'Julius is yellow' or both then Bernhard is green. It is improbable that if 'Julius is yellow and Mary went to the bedroom' then Brian is a frog.
hypothesis: It is likely that either 'Mary went to the bedroom' or 'Bernhard is green' but not both.
valid_hypothesis: We doubt that either 'Mary went to the bedroom' or 'Bernhard is green' but not both.
invalid_hypothesis: It is likely that either 'Mary went to the bedroom' or 'Bernhard is green' 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
    0.1::factA.
    0.25::factB.
    0.25::factC.
    %hop1
    0.02::factX:-or(factA,factB).
    0.25::factY:-or(factC,factA).
    0.1::factZ:-and(factA,factC).
  
    %hop2
    conclusion:-xor(factC,factY).
  
    query(conclusion).
    
hypothesis_assertion: Either 'Mary went to the bedroom' or 'Bernhard is green' but not both.