Abstract: A method of propagating changes in a design model identifies a change to a changed element, creates steps to carry out the change, creates additional steps based on the change and on relationships between the changed element and other elements in the design model, and executes the steps to alter the model in a manner that reflects the change. The steps may be created in a manner that depends on other steps that have been created. A system for regenerating a design model comprises a model element, a step propagator, and a step executor. The step propagator receives a first step that represents changes in the model element, and produces a second step that represents other changes in the model element that are dependent on the first step, and the step executor executes the first and second steps.

Abstract: A method of propagating changes in a design model identifies a change to a changed element, creates steps to carry out the change, creates additional steps based on the change and on relationships between the changed element and other elements in the design model, and executes the steps to alter the model in a manner that reflects the change. The steps may be created in a manner that depends on other steps that have been created. A system for regenerating a design model comprises a model element, a step propagator, and a step executor. The step propagator receives a first step that represents changes in the model element, and produces a second step that represents other changes in the model element that are dependent on the first step, and the step executor executes the first and second steps.

Abstract: A method of propagating changes in a design model identifies a change to a changed element, creates steps to carry out the change, creates additional steps based on the change and on relationships between the changed element and other elements in the design model, and executes the steps to alter the model in a manner that reflects the change. The steps may be created in a manner that depends on other steps that have been created. A system for regenerating a design model comprises a model element, a step propagator, and a step executor. The step propagator receives a first step that represents changes in the model element, and produces a second step that represents other changes in the model element that are dependent on the first step, and the step executor executes the first and second steps.

Abstract: A method that includes (1) distributing authorization keys from a subscription server to computers on which copies of an application program are to be run, each of the authorization keys being associated with a validity period during which the authorization key will be valid, and (2) at intermittent times that may be as infrequent as the times when the validity periods end, distributing new authorization keys to each of the computers, the keys being distributed electronically in a manner that is transparent to users of the computers.

Abstract: A method of propagating changes in a design model identifies a change to a changed element, creates steps to carry out the change, creates additional steps based on the change and on relationships between the changed element and other elements in the design model, and executes the steps to alter the model in a manner that reflects the change. The steps may be created in a manner that depends on other steps that have been created. A system for regenerating a design model comprises a model element, a step propagator, and a step executor. The step propagator receives a first step that represents changes in the model element, and produces a second step that represents other changes in the model element that are dependent on the first step, and the step executor executes the first and second steps.

Abstract: A method that includes (1) distributing authorization keys from a subscription server to computers on which copies of an application program are to be run, each of the authorization keys being associated with a validity period during which the authorization key will be valid, and (2) at intermittent times that may be as infrequent as the times when the validity periods end, distributing new authorization keys to each of the computers, the keys being distributed electronically in a manner that is transparent to users of the computers.