A pumping lemma for a class of languages \varvec{\mathcal {C}} is often used to show particular languages are not in \varvec{\mathcal {C}}. In contrast, we show that a pumping lemma for a class of languages \var
One can ask the question whether also non-trivial (non-constant) solutions atf_1=0may be continued into the regime off_1>0. This depends on two issues: existence and non-degeneracy of a non-trivial solution of (3) forf_1=0. First we note that for\omega =0, there is a plethora o...