Patent ID: 7441015

Claim:
A method of undoing execution of a function requested by a first client station on a computer object stored on a server station of a communication network, comprising the following steps: receiving, from a client station, a request to undo execution of the function on the computer object, the execution of the function being an operation to manipulate the object from an earlier state of the object to a manipulated state of the object; obtaining, on said server station, the earlier state of the manipulated object; generating electronic money on the server station, associated with the first client station; sending a response to the first client station via the communication network, the response comprising a sum of said electronic money comprising at least one electronic money coin, less than or equal to an execution cost received by the server station for the execution of said function; and calculating an undo cost associated with the received undo request, wherein the sum of electronic money included in the response to the first client station is calculated after deduction of the undo cost, wherein the undo cost is zero if the number of requests for executions of undone functions sent by the client station is less than a predetermined threshold value.