Tree automata with one memory have been introduced in 2001. They generalize both pushdown (word) automata and the tree automata
with constraints of equality between brothers of Bogaert and Tison. Though it has a decidable emptiness problem, the main
weakness of this model is its lack of good closure properties.
We propose a generalization of the visibly pushdown automata of Alur and Madhusudan to a family of tree recognizers which
carry along their (bottom-up) computation an auxiliary unbounded memory with a tree structure (instead of a symbol stack).
In other words, these recognizers, called visibly Tree Automata with Memory (VTAM) define a subclass of tree automata with
one memory enjoying Boolean closure properties. We show in particular that they can be determinized and the problems like
emptiness, inclusion and universality are decidable for VTAM. Moreover, we propose an extension of VTAM whose transitions
may be constrained by structural equality and disequality tests between memories, and show that this extension preserves the
good closure and decidability properties.