SOLUTION

• Presentation are the functions that any system with a user interface must provide.
• Presentation and Application are the functions that any system with a user interface must provide.
• Access control maybe provided to let only authorized users join the interface and add applications to it.
• Moreover, the commands of the users who are allowed to join may be restricted.
• For instance, some users may be prevented from inputting any command, which is useful in a presentation.