/*
    mortal/1
    mortal(X)

    Second, more complicated version of the of the predicate mortal.
    X is mortal if X is is a man and X is not Jesus.

    Warren Sack <wsack@ucsc.edu>
    May 2017
	
*/

man(jesus).
man(socrates).
man(plato).
       
equal(X,X).
       
mortal(X):- man(X),not(equal(X,jesus)).