:- [tsg].

article :-
	name(FileName, "article.pl"),
	open(FileName,write,Stream),
	sigma_tsg(tsg(i,[i,x,y],[(i -> f(x,y)),
	     (x -> zero),
	     (y -> zero),
	     [(x -> suc(x)), (y -> suc(suc(y)))]
	    ]),Stream),
	close(Stream).