Abstract: The invention is essentially characterized in that two different schema branch codes are used, whereby one of the two is utilized far more frequently and, as a consequence, effects a compression. The schema branch code and position code are combined, and the bit length for the schema branch code is transmitted therewith. This results in simplifying the search function in such a manner that the first part, alone, specifies the type of the referenced element and that an improvement in the extensibility is achieved based on a schema version number to be transmitted and on firmly prescribed extension strategies that are also familiar to the decoder.