Methods and apparatus, including computer program products, for searching for one or more logical elements in a hierarchical tree structure of an extended markup language document conforming to a schema used for XML. The method includes the steps of (1) providing a representation of an extended markup...http://www.google.com.hk/patents/US7877400?utm_source=gb-gplus-share專利 US7877400 - Optimizations of XPaths
