## Thursday, November 15, 2012

### Now listed with the American Institute of Mathematics

Applied Discrete Structures is now listed among the Approved Textbooks by the American Institute of Mathematics as part of their Open Textbook Initiative.

The American Institute of Mathematics (AIM) seeks to encourage the adoption of open source mathematics textbooks. The AIM Editorial Board has developed evaluation criteria to identify open source books that are suitable for use in traditional university courses. The Editorial Board maintains a list of Approved Textbooks which have been judged to meet these criteria.

If you're looking for a text for a college/university mathematics course, consider books on this list!

# New Sage Worksheet: Trees

I was updating a few things in Chapter 10, Trees, and took the opportunity to do a few things with Sage. ADS2_Trees.sws
• Cataloging trees by degree sequence.
• Finding a minimal spanning tree using Kruskal's algorithm.
• The binary tree sorting algorithm
Actually, the last item only uses Python.

## Saturday, October 13, 2012

### Video illustrating the construction of minimal spanning trees.

I've been tweeking Chapter 10 (Trees) and put together a short example of how to construct a minimal spanning tree for a weighted undirected graph.

## Saturday, August 4, 2012

### Revised version of Chapter 6: Relations

A revised version of Chapter 6 is now available. It will become part of Version 2 of the larger pdf versions of Applied Discrete Structures in 2013. The most significant changes are:

• Hasse diagrams are not introduced until partial orderings are defined, avoiding some confusion that was reported with the original version of the chapter.
• Congrence modulo m has been added as an example of an equivalence relation on the integers.
Click here to get either a pdf or Mathematica Notebook of Chapter 6

## Wednesday, April 18, 2012

### Sage notebook on relations

I filled in for Al Doerr in his class this morning and he asked me to cover some material on relations. So I took that opportunity to figure out how to implement some relations in Sage. It went pretty well. One exception is that in squaring an adjacency matrix of a relation, I'd like to get a simple adjacency matrix with just 0's and 1's. The way I did the calculations, I got the numbers of different paths of length 2 connecting the vertices. That's fine except that the graphs of the squared relations become messy. If anyone knows how to fix this, I'd appreciate the help.

http://www.sagenb.org/home/pub/4715

## Wednesday, April 4, 2012

### Two Part Version of Applied Discrete Structures

Applied Discrete Structures is now available in either a single volume or in a two part version:
Part 1 - Fundamentals
Part 2 - Algebraic Structures
It broken according to how the two semesters of discrete math are taught at UMass Lowell. We did this for a few reasons. One is that many of our students only need to take the first semester. Also, the full version, whether as a pdf or a printed book, is quite large (484 pages).

Information on the one and two part versions (as free pdf's or printed copies from lulu.com) is available on our web site:

## Tuesday, March 20, 2012

### Change in Creative Commons License

It's come to my attention that the Creative Commons License that we had posted:

did not allow instructors to bundle selected chapters for distribution to students due to the "no derivatives" restriction. This wasn't our intent, in fact this is precisely what we do for instructors at UMass Lowell. To remedy the situation, the following license has been posted on our web site.

Most of the existing files still list the No Derivatives restriction a this time, but they will be updated as we proceed.

## Thursday, March 1, 2012

### Full Text now available on lulu.com

Version 1.0 of the text, all 16 chapters with solutions to odd-numbered exercises is now available on lulu.com.

## Thursday, February 2, 2012

### Solutions to Chapter 14 (odd numbers) added

We've reached a milestone today, with the final bit of solutions to the odd numbered exercises in the main body of the book being added to the wiki site. The solutions to problems in Chapter 14 were just added. The only things left to add are the appendices, which were on determinants and algorithms, and the references. Both need to be updated considerably, so that might take a while.