Context is a central notion in hEIDI. Basically, it contains identification results, i.e. a set of proteins identified by a set of peptides.
There are two types of contexts in hEIDI:

• Search context: each identification result from Mascot, or from any other identification engine, is automatically “encapsulated” into one Search context.
• User context: it is created by the user in order to gather together several identification results into a User context. In order to have non-redundant sets of proteins for a given context, proteins need to be grouped to build “Protein Groups”.

A User context is represented by .
A User context contains either child contexts or identifications but can't have both at the same level.

There are multiple reasons for grouping several identifcations under the same User context:

• Same biological origin
• Same gel
• Same culture condition
• Same chromatographic column
• …

Search context is represented by .