ERD Partitipation - what does it for?

[Csányi Pál <csanyipal gmail com>]

Hi,

I am working on an ER Diagram in Dia version 0.97.3.

There are in ER toolbox Entity, Weak Entity, Relationship, Attribute
and Participation.

I understand all but the Participation. What does it for? What is it for?

What is the difference between Participation and a line on which was
setup for a Cardinality at one, or both end?

Is there a documentation about Participation theory somewhere on the
Internet out there?

-- 
Best, Pali