28. A method implemented by an apparatus for processing a response to a request for updating a previously supplied electronic document related to a schedule of broadcasting a plurality of television broadcast programs in a program broadcast system, wherein said previously supplied electronic document is stored in a client of the program broadcasting system and has a hierarchical structure based on a prescribed syntax, the hierarchical structure including an upper fragment and a plurality of lower fragments located below the upper fragment in the hierarchical structure to describe, for each of the scheduled television broadcast programs, a program identifier, a title, broadcast information and corresponding program content information, the method comprising: receiving at the client an update document from a provider in the program broadcasting system, the update document having a structure based on the prescribed syntax and including the upper fragment and an invalid element to delete a first lower fragment of said previously supplied electronic document, wherein said invalid element indicates that said first lower fragment is invalid, and wherein said invalid first lower fragment is identified by the invalid element and is related to one of the scheduled television broadcast programs; identifying in the previously supplied electronic document said invalid first lower fragment identified by said invalid element at said client; and controlling to delete said identified invalid first lower fragment from the previously supplied electronic document at said client.
28. A method implemented by an apparatus for processing a response to a request for updating a previously supplied electronic document related to a schedule of broadcasting a plurality of television broadcast programs in a program broadcast system, wherein said previously supplied electronic document is stored in a client of the program broadcasting system and has a hierarchical structure based on a prescribed syntax, the hierarchical structure including an upper fragment and a plurality of lower fragments located below the upper fragment in the hierarchical structure to describe, for each of the scheduled television broadcast programs, a program identifier, a title, broadcast information and corresponding program content information, the method comprising: receiving at the client an update document from a provider in the program broadcasting system, the update document having a structure based on the prescribed syntax and including the upper fragment and an invalid element to delete a first lower fragment of said previously supplied electronic document, wherein said invalid element indicates that said first lower fragment is invalid, and wherein said invalid first lower fragment is identified by the invalid element and is related to one of the scheduled television broadcast programs; identifying in the previously supplied electronic document said invalid first lower fragment identified by said invalid element at said client; and controlling to delete said identified invalid first lower fragment from the previously supplied electronic document at said client. 60. The method of claim 28 , wherein the invalid element in the update document includes the invalid first lower fragment.