# MCSN Tuesday, 1-Nov-11

# Quiz

- page 1 - bravo!
- page 2, mainly bravo, but a few common misconceptions remain:
- components can't overlap (because they're maximal)
- cores: can't be determined from degree. For one thing, a vertex in the 4-core has to be connected to at least 4 others in the 4-core (by definition!). Therefore the smallest 4-core will have 5 vertices. Some people indicated a
*single node*as belonging to the 4-core. - cliques: are defined to be maximal. So a triad isn't necessarily a clique, though if it's not a clique on its own it must be
*part*of a larger clique. Note also that a*square*is not a clique unless it contains its*diagonals*.

# 4.8

# Affiliation networks

- People affiliate to groups (often defined by space, like the University of Alberta), and events (typically defined by space-time, like this class session), whether by choice or circumstance.
- Such affiliations define
*bipartite*networks comprising two kinds of vertex, which we can call*actors*and*events*(don't be confused -*events*could be more like groups) - In a
*bipartite*network there are two kinds of vertex, type A and type B. All lines connect a type A vertex to a type B vertex - there are no direct connections between vertices of type A, nor are there direct connections between vertices of type B. - Example: Interlocking directorates