The paper introduces a grammar formalism for defining the set of sentences in a language, a set of labeled trees (not the derivation trees of the grammar) for the representation of the interpretation of the sentences, and the (possibly non-projective) correspondence between subtrees of each tree and substrings of the related sentence. The grammar formalism is motivated by the linguistic approach (adopted at GETA) where a multilevel interpretative structure is associated to a sentence. The topology of the multilevel structure is 'meaning' motivated, and hence its substructures may not correspond projectively to the substrings of the related sentence. .
