'********** variable elimination 'Tweety has wings. <{Tweety} --> [with-wings]>. 'If something can chirp and has wings, then it is a bird. <(&&,<$x --> [chirping]>,<$x --> [with-wings]>) ==> <$x --> bird>>. 23 'If Tweety can chirp, then it is a bird. ''outputMustContain('<<{Tweety} --> [chirping]> ==> <{Tweety} --> bird>>. %1.00;0.81%')