Equivalence of Deterministic Nested Word to Word Transducers

International audienceWe study the equivalence problem of deterministic nested word to word transducers and show it to be surprisingly robust. Modulo polynomial time reductions, it can be identified with 4 equivalence problems for diverse classes of deterministic non-copying order-preserving transducers. In particular, we present polynomial time back and fourth reductions to the morphism equivalence problem on context free languages, which is known to be solvable in polynomial time

Nested Regular Expressions can be Compiled to Small Deterministic Nested Word Automata

International audienceWe study the problem of whether regular expressions for nested words can be compiled to small deterministic nested word au-tomata (NWAs). In theory, we obtain a positive answer for small deter-ministic regular expressions for nested words. In practice of navigational path queries, nondeterministic NWAs are obtained for which NWA de-terminization explodes. We show that practical good solutions can be obtained by using stepwise hedge automata as intermediates

Weak Inclusion for XML Types ⋆

Abstract. Considering that the unranked tree languages L(G) and L(G ′ ) are those defined by given non-recursive XML types G and G ′,this paper proposes a simple and intuitive method to verify whether L(G) is “approximatively ” included in L(G ′). Our approximative criterion consists in weakening the father-children relationships. Experimental results are discussed, showing the efficiency of our method in many situations.