On a family of L languages resulting from systolic tree automata

Recent work on systolic tree automata has given rise to a rather natural subfamily of EOL languages, referred to as systolic EOL languages in this paper. Systolic EOL languages possess some remarkable properties. While their family contains (because of its closure under Boolean operations) intuitively quite complicated languages, it still has decidable equivalence problem. Especially interesting is the fact that similar decision problems for slightly more general families lead to the celebrated open problems concerning Z-rational power series.