Before revision: A compressed index is a data structure representing a text within compressed space and supporting fast count and locate queries: count/return all positions where a pattern occurs. The first compressed indexes operate within a space bounded by the text's entropy. Entropy, however, is insensitive to long repetitions. For this reason, in recent years more powerful compressed indexes have emerged; these are based on  the Lempel-Ziv factorization, the run-length BWT, context-free grammars and, more recently, string attractors.
After revision: In this paper, we consider the problem of compressing a trie while supporting the powerful the Lempel-Ziv factorization, the run-length BWT, context-free grammars and, more recently, string attractors.