function [pp,ss] = get_ndparents(NFSA,q)
% returns list of parents of q in NFSA

% quite a bit less elegant than the deterministic version
pp=[];
ss='';
for p=NFSA.Q
  for s=NFSA.ALF
    R = nfsa_delta(NFSA,p,s);
    if ismember(q,R)
      pp(end+1)=p;
      ss(end+1)=s;    
    end
  end
end

return