A Pumping Lemma for Output Languages of Attributed Tree Transducers

The concept of attributed tree transducer is a formal model for studying properties of attribute grammars In this paper for output languages of noncircular producing and visiting attributed tree transducers we introduce and prove a pumping lemma We ap ply this pumping lemma to gain two results there is no noncircular producing and visiting attributed tree transducer which computes the set of all monadic trees with expo nential height as output and there is a hierarchy of noncircular producing and visiting attributed tree transducers with respect to their number of attributes