check(C,N):- C is N mod 2.odd(N) :- check(C,N) is 1.
?- odd(1).
GNU Prolog 1.3.1 By Daniel Diaz Copyright (C) 1999-2009 Daniel Diaz uncaught exception: error(syntax_error('user_input:1 (char:4) . or operator expected after expression'),read_term/3)
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