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  1. father(zeb, john_boy_sr).
  2. father(john_boy_sr, john_boy_jr).
  3.  
  4. ancestor( X, Y) :-
  5.     father( X,Y).
  6.  
  7. ancestor( X, Y) :-
  8.     father( X, Z), ancestor(Z, Y).
  9.  
  10. ?- ancestor(zeb, john_boy_jr).
  11.  
Compilation error #stdin compilation error #stdout 0s 0KB
comments (?)
stdin 
Standard input is empty
compilation info 
prog.pl:10:4: syntax error: . or operator expected after expression
	1 error(s)
compilation failed
stdout 
Standard output is empty
https://ideone.com/f5qFk
language:
Prolog (gprolog 1.4.5)
created:
14 years ago
visibility:
public

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