Abstract: An interactive computer configuration system is an aid for a sales person or a customer to make it easy to grasp and configure a huge configuration problem. The user interacts with the computer system and makes many choices successively, and a configuration engine checks each choice for validity. The configuration engine comprises a configuration model defining mutual predefined relations between the selectable elements and comprises programs for validating a set of choices against said configuration model. The invention relates to the situation where a requested choice made by the user corresponds to an invalid configuration instance. According to the invention, the user is allowed to insist on this choice and an alternative investigation system according to the invention will present to the user a number of relevant proposals for undoing choices made previously so that a valid configuration instance can be obtained.

Abstract: There is provided a method of controlling the flow of information in a client/server system for interactive configuration, wherein a request to a rule base is processed, comprising the steps of: providing request information, resulting from a first client interaction; transferring said request information to the server; collecting intermediate information, resulting from at least one second client interaction succeeding said first client interaction; creating response information on the server responsive to said request information; transferring said response information to the client; determining whether said response information indicates conformity with said rule base; creating merged information responsive to said intermediate information and said response information; determining whether said intermediate information represents a higher level of knowledge than said response information; selecting at least one of the following actions according to said determinations: use said merged information to update