Chapter 1: Introduction

  1. What is reductionism?
  2. When a problem is reduced, why is it hard to put the pieces back together again?
  3. What is the connection between reductionism and optimization?
  4. What are some examples of networks?

Chapter 2: The Random Universe

  1. What property of the Koinigsberg bridge graph leads to the conclusion that no path traversing each bridge exactly once exists?
  2. What is a random graph?
  3. What did A. Einstein mean when he said "God does not play dice with the universe"?
  4. What do the terms percolation, giant component, and community have in common?

Chapter 3: Six Degrees of Separation

  1. Find the Kevin Bacon link at UVA and look at the material there.
  2. How is Milgram's experiment similar (or not) to how you use google to help you find information?
  3. What does step 4 (on page 28) of Milgram's experiment mean with respect to graphs?
  4. What does the term "small world" mean?
  5. Why did no one know what the structure of the WWW was before 1999?
  6. Why is it still hard to find what you want on the web if everything is only a few clicks away?

Chapter 4: Small Worlds

  1. What is the importance of weak social ties?
  2. Do you agree with Branovetter's description of the U.S. social network? Why or why not?
  3. Why does clapping synchronize?
  4. How de we compute a clustering coefficient for a group of friends?
  5. What is the Erdos number of Underwood Dudley? What is his connection to Professor Kincaid?
  6. What is going on in Figure 4.2? Explain.
Chapter 5: Hubs and Connectors

  1. What did Gladwell's statistical distribution in his 2000 book have to do with scale-free networks?
  2. If the web is not democratic what political system does it mimic? Explain why.
  3. What made the Bacon website so popular? Can fads be manufactured? predicted?
  4. If the number of movies an actor has been in does not drive the vertex degree in the network then what does?
  5. What is a hub's role in a disease transmission network? a computer network?

Chapter 6: The 80/20 Rule

  1. What is Pareto's contribution to optimization?
  2. What does Barabasi mean by the term scale-free?
  3. What do the plots of e^x, x^2 and x^3 look like on Cartesian coordinate paper, semi-log paper and log-log paper?
  4. What power law did Pareto uncover?
  5. How does order emerge from chaos?
  6. What does self-organization have to do with scale-free networks?

Chapter 7: Rich get Richer

  1. What does the "age" of a node have to do with its degree?
  2. What does a growing "random" network look like? What are its shortcomings?
  3. If perferential attatchment means the "rich get richer", how do we explain nodes that lose popularity?
  4. What does the "the number of nodes with exactly degree k follows a power law for any value of k" mean?
  5. Are links only added to a real network when a node appears? Explain.
  6. Are growing networks that exhibit power laws the result of a phase transition from disorder to order? Why or why not?

Chapter 8: Einstein's Legacy

  1. What does fitness mean for nodes in a network?
  2. How do we measure fitness?
  3. Explain how preferentical attatchment with fitness would work?
  4. What was the key to Bose's model of quantum theory?
  5. Explain how the physics model maps to a network?
  6. What does the presence of a Bose-Einstein condensate mean in network terms?
  7. Explain the two types of dynamic evolving networks that Barabasi proposes.
  8. What fitness distributions make sense to use?

Chapter 9: Achilles' Heel

  1. In what way are scale-free networks robust?
  2. What would a plot of network performance vs. random node failures look like for a scale-free network?
  3. Assuming that ecosystems are scale-free networks what species should we protect?
  4. Explain how a cascading failure works for a particular instance of a scale-free network.
  5. Are forest fires an example of a cascading failure? How has protecting against forest fires made them worse?

Chapter 10: Viruses and Fads

  1. Have you noticed any new `instant' celebrities or products? If so what are they?
  2. What does the normal distribution have to do with innovation? Explain.
  3. What do the terms network diffusion, critical threshold and spreading rate mean?
  4. How are traffic jams like a viral epdemic?
  5. Why do viruses like Lovebug and AIDS persist?
  6. What is the connection between percolation and a critical threshold of zero in scale-free networks?
  7. How do we create a nonzero epdemic threshold in scale-free networks?

Chapter 11: The Awakening Internet

  1. Have you ever had any ideas people thought were crazy? If so, what were they?
  2. What were the key components to the birth of the internet?
  3. Why map the internet?
  4. What is a success disaster?
  5. How does preferential attachment play a role in the addition of new nodes to the internet?
  6. What conflicting objectives does the author claim the internet addresses?
  7. What is parasitic computing? How is it different from distributed computing?

Chapter 12: The Fragmented Web

  1. Why can we only reach less than 1/4 of all web documents?
  2. Be able to discuss the continent structure (Fig. 12.1) and give examples of each of the 4 continents.
  3. Why do these continents persist?
  4. What is the definition of a web community?
  5. Why are people interested in finding them?
  6. What does Lessy's quote on page 133 mean?
  7. What does the author mean when he says "code can curtail behavior but it cannot prescribe archtitecture?
  8. What purpose could the web archive serve for understanding scale-free networks?

Chapter 13: The Map of Life

  1. Rather than a single gene triggering a genetic disorder our author claims a different trigger. What is it?
  2. What is the difference between a gene's structural and functional roles?
  3. Cells in our bodies are not growing. Yet evolutionary forces have been at work. Why are many of the network features of the cell scale-free?
  4. Metabolic networks for 43 organisms of varying size were studied by the author. Each network had a diameter of 3. What is the explanation? What are the implications?
  5. What is one possible explanation for the scale-free structure of networks in cells? (section 6)
  6. Read the sentence that begins on the bottom of page 192. What explanation is given for the failure of many cancer treatments?

Chapter 14: Network Economy

  1. Why do corporate mergers make sense in the language of scale-free networks?
  2. If the hierarchical tree structures of traditional mass production oriented corporations is no longer valid what network model is?
  3. Why do the boards of the Fortune 1000 corporations form a scale-free network?
  4. What are the similarities between U.S. power grids and the world economy of companies and financial institutions?
  5. How does viral marketing work?
  6. What network effects do businesses need to understand to succeed?

Chapter 15: Web Without a Spider

  1. What does the title of the chapter mean?
  2. Most of the properties we have discussed (degree distribution, clustering, shortest path distances, etc.) are static. Why do these properties have an effect on the dynamic features of networks (e.g. traffic flow)?

Chapter 16: Hierarchies and Communities

  1. How do cells multitask?
  2. Why is modularity at odds with properties of scale-free networks?
  3. Verify the clustering coefficients calculations for the central node in Fig. 16.1 (B), (C), and (D).
  4. What is hierarchical clustering? How does it merge modularity and power laws?
  5. What are the roles of hubs in hierarchical modularity?