context: It is impossible that Lily is gray. There is a better than even chance that Brian is a swan. It is certain that Julius is a frog. It is highly likely that if 'Lily is gray' or 'Julius is a frog' or both then Sandra left the milk. There is little chance that if either 'Brian is a swan' or 'Julius is a frog' but not both then Mary went to the hallway. It is certain that if 'Brian is a swan' or 'Julius is a frog' or both then John took the apple.
hypothesis: It is highly unlikely that 'Mary went to the hallway and Julius is a frog'.
valid_hypothesis: It is highly unlikely that 'Mary went to the hallway and Julius is a frog'.
invalid_hypothesis: Chances are about even that 'Mary went to the hallway and Julius is a frog'.
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
    0.0::factA.
    0.6::factB.
    1.0::factC.
    %hop1
    0.9::factX:-or(factA,factC).
    0.1::factY:-xor(factB,factC).
    1.0::factZ:-or(factB,factC).
  
    %hop2
    conclusion:-and(factY,factC).
  
    query(conclusion).
    
hypothesis_assertion: 'Mary went to the hallway and Julius is a frog'.