context: We believe that Sandra left the football. We believe that Lily is a swan. There is a better than even chance that Emily is a mouse. It is impossible that if 'Sandra left the football and Emily is a mouse' then Winona is a sheep. It is certain that if 'Lily is a swan and Sandra left the football' then Gertrude is a cat. It is probably the case that if 'Emily is a mouse' or 'Sandra left the football' or both then Brian is white.
hypothesis: It is improbable that 'Gertrude is a cat' or 'Brian is white' or both.
valid_hypothesis: There is a very good chance that 'Gertrude is a cat' or 'Brian is white' or both.
invalid_hypothesis: It is improbable that 'Gertrude is a cat' or 'Brian is white' or 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
    0.75::factA.
    0.75::factB.
    0.6::factC.
    %hop1
    0.0::factX:-and(factA,factC).
    1.0::factY:-and(factB,factA).
    0.7::factZ:-or(factC,factA).
  
    %hop2
    conclusion:-or(factY,factZ).
  
    query(conclusion).
    
hypothesis_assertion: 'Gertrude is a cat' or 'Brian is white' or both.