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