Source PostScript (subc.pps)

%% soustraction de 2 complexes
%% syntaxe : a b a' b' subc --> z - z'
/subc {
4 dict begin
   /b' exch def
   /a' exch def
   /b exch def
   /a exch def
   a a' sub
   b b' sub
end
} def