1
Introduction

Problems

• End-of-chapter problems 1.1-1.3

Provocations

• What is the difference between a network and a group?

  • One thought is that groups are sets of nodes, and networks represent the structure of relationships among those nodes

• Are networks real or just analytical devices?

  • Networks provide a compelling lens through which to the see the world. We see networks in everything from molecules, brains, economies, to ecologies. So, one view is that ties are real, and groups are real, but the notion of a network is more of an analytical device.

  • On the other hand, maybe it's silly to argue that ties and groups have more reality than networks: they are all analytical constructs at some level. And networks are certainly real in the sense that their characteristics have consequences. Centrality predicts many outcomes. If networks represent the structure of relationships in a group