Social Networks Class 11

study for final; main concepts: (cohesive subgroups, components, cliques, n-cliques, k-cores, partitioning & community detection, hierarchial cluster analysis

What is a cohesive subgroup?

A group of people who interact more with each other than with people outside the group. These groups are also called communities, clusters, or modules.

What are the two questions we ask when identifying cohesive subgroups?

How connected are members within the group? How different are they from outsiders?

What is a component?

A subgroup where everyone can reach everyone else through direct or indirect ties, and there are no outside links.

What is a clique?

A maximal complete subgraph where every member is directly connected to every other member. Must have 3 nodes.

What does "maximal" mean in a clique?

You can’t add any more nodes without losing full mutual connections

What are the limitations of cliques?

Fragile, if one tie breaks, it completely falls apart.

What is an n-clique?

All members are connected within n steps instead of directly.

What is a 2-clique?

A group where every node can reach others within 2 steps.

What is a k-core?

A group where each member has at least k ties to others within the group. Helps detect dense core groups.

What is partitioning in network analysis?

You define the group size/# before hand. Dividing a network into a specified number of groups based on certain algorithms.

What is community detection?

a method used to find groups (communities) in a network without being told what the groups are ahead of time.

What is hierarchical clustering?

A bottom-up method where nodes are merged into bigger clusters based on their similarity or distance.