An assumption in the r-model is that the underlying hypertext is to be permitted to be used in a distributed environment. The visible hypertext level reflects this assumption. Each visible HT segment is associated with a separate user and display. Each segment presents on or more of the active concrete windows to its viewer. The model does not prevent the display of a particular concrete window in more than one segment. Whether (and how) the effects of user interactions to one display may affect what is shown on other user displays is a property of the hypertext model, and not of the r-model.