In advanced search, we start by indicating what we are searching for (skill, activity or groups/users)

We then can add filters on:

For all types:

• the value of one of the fields
• one or more skills/activity/groups we search within (it searches within the intersection of these items)
• one or more skills/activity/groups it must contain

For activities and skills

• skills that are prerequisites of it
• what did a group or user do so far on it

For activities

• an activity that unlocks it (?)
• skills that it contributes to
• groups that have a session on it (we can select a group, indicate a date/time interval, and potentially other options such as a price)

For skills

• skills it is a prerequisite of
• activities that contribute to it

For groups

• skills or activities that it has validated
• date/time interval, price, …