Unstructured p2p database systems are usually characterized by the presence of schema mappings among peers. In these systems, the detection of corrupted mappings is a key problem. A corrupted mapping fails in matching the target or the source schema, hence it is not able to transform data conforming to a schema into data conforming to a schema , nor it can be used for effective query reformulation.
This paper describes a novel technique for maintaining mappings in XML p2p databases, based on a semantic notion of mapping correctness.