We can see that some contexts are connected by a line, and each connection line contains an *u* and a *d*. This letters have meanings:

- **u**, short from *up*, means that that end of the connection is sharing information;
- **d**, short from *down*, means that that end of the connection is receiving information;

All this connections between contexts can be justified:

|    **Receiver**    |     **Sender**     |                                                                                     **Justification**                                                                                     |
|:------------------:|:------------------:|:-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------:|
|      **Items**     | **Authentication** | Some item related actions require authentication, to ensure that it is a trust-worthy user executing them                                                                                 |
|                    |      **Meals**     | Some item related actions require meal information (i.e.: show item ingredients, allergens and nutritional values)                                                                        |
|                    |       **POS**      | Some item related actions require POS information (i.e.: indicate where the item currently is available)                                                                                  |
|      **Logs**      | **Authentication** | Some logs related actions require authentication information, to record who authenticates in the application, and when                                                                    |
|                    |      **Items**     | Some logs related actions require items information, to record who creates new items (or updates them), and when                                                                          |
|                    |      **Meals**     | Some logs related actions require meals information, to record who creates new meals (or updates them), and when                                                                          |
|      **Meals**     | **Authentication** | Some meal related actions require authentication, to ensure that it is a trust-worthy user executing them                                                                                 |
| **Points of Sale** | **Authentication** | Some POS related actions require authentication, to ensure that it is a trust-worthy user executing them                                                                                  |
|    **Purchases**   | **Authentication** | Some purchase related actions require authentication, to ensure that it is a trust-worthy user executing them. Also, some actions also need the logged in user information to be recorded |
|                    |      **Items**     | Some purchase related actions need items information, in order to record which item is purchased (or to view which item was sold)                                                         |