Day 26 mat385

• Announcements:
  • I hope the exam went well. I haven't looked at them yet, as you might expect (since I just got back from Utah yesterday). Steve Wilkinson reports that there were no riots.

  • Your homework for 4.1 returned (graded 6 and 7).
    • General impression for the class: sloppy work.
    • If you didn't do #7, then you certainly missed the point of the exercise.
    • If you don't know how to do something, or don't know why we're doing it, ask me; come and see me. That's why I'm here!

  • Homework assignment for 5.1 is due on Wednesday.

• We'll polish off section 5.1: Graphs

• Then we'll start section 5.2: Trees and their representations

Links:

• Graph Terminology Handout
• Adjacency matrix example (directed)
• Tree Terminology Handout
• Tree Traversal

• Reverse Polish Notation
• No need to restrict Euler's formula to simple graphs! If you find a theorem with restrictions, ask yourself why the restrictions are there! (Now: is connectedness important?)
• Graph Isomorphism (and planar)
• Complete Graphs

• NIST (the National Institute of Standards and Technology) defines a tree as "A connected, undirected, acyclic graph". Our book does not require the "undirected" part, and many sources assume that a tree is directed! This does, unfortunately, add to the confusion.... An ordered tree is one where the children are numbered (there is a left to right), which is important for tree traversal.

• NIST (the National Institute of Standards and Technology) Dictionary of Algorithms and Data Structures