There is little chance that Bernhard is a frog. It is highly unlikely that Sumit is tired. It is highly likely that Greg is a frog. We doubt that if 'Sumit is tired and Greg is a frog' then Emily is a wolf. Chances are about even that if 'Sumit is tired' or 'Bernhard is a frog' or both then Mary went to the bedroom. There is a better than even chance that if either 'Bernhard is a frog' or 'Greg is a frog' but not both then Brian is yellow.
There is a very good chance that 'Emily is a wolf and Mary went to the bedroom'.
It is impossible that 'Emily is a wolf and Mary went to the bedroom'.
There is a very good chance that 'Emily is a wolf and Mary went to the bedroom'.

  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.
  0.05::factB.
  0.9::factC.
  %hop1
  0.2::factX:-and(factB,factC).
  0.5::factY:-or(factB,factA).
  0.6::factZ:-xor(factA,factC).

  %hop2
  conclusion:-and(factX,factY).

  query(conclusion).
  
'Emily is a wolf and Mary went to the bedroom'.