Representing Networks

• N = {1,...,n} nodes, vertices, agents, actors, players...

• edges, links, ties: connections between nodes

  • They may have intensity (weighted)
  • How many hours do two people spend together per week?
  • How much of one country's GDP is traded with another?

• They may just be 0 or 1 (unweighted)

  • Have two researchers written an article together?
  • Are two people "friends" on some social platform?

• They may be "undirected" or "directed"

  • coauthors, friends,..., relatives, spouses, ..., are mutual relationships
  • link from on web pages to another, citations, following on social mediam,... one way

Undirected Network:

Or list the links:

g = {{1,2}, {1,4}, {2,4}, {3,4}}

g = {12,14,24,41,43}

order of pairs matters