## Tuesday, June 15, 2010

### Another post on Martin Gardner

(I will post about CCC 2010 later in the week.)

Several people have posted on the death of Martin Gardner: I did not because of travels, but now I can. (Full Disclosure- This Blog is part of the Scientific American Partner Network. Martin Gardner had a column in SA for many years.)

About a year and a half ago I reviewed some books of Martin Gardner for my SIGACT NEWS Book Review Column. (The review is in this column.) Before I send in a review I contact all of the authors of books, authors of reviews, and editors of the books and send them a copy of the review (by email). I was told that Martin Gardner didn't use email (he was 94 years old!). So I sent him the review by postal mail (you can ask your grandfather what that was).

I got a response! I posted it here though I blocked out his address and phone number for privacy reasons. As you can see the letter is coherent and cogent (I've gotten less coherent letters from people half his age). It is good to know that he was sharp till the end.

The first theorem I ever read on my own was in one of his books: it was that (in today's terms) a graph is Eulerian iff every vertex has even degree. (ADDED LATER: The correct theorem is that a graph is Eulerian (has a cycle that hits every edge exactly once) iff it is connected and every vertex has even degree.) I also learned about The Unexpected Hanging from one of his columns. These two stand out the most; however, I learned A LOT from his columns, plus I learned that there was more to math than what was taught in the classroom.

1. Typos:
1) "a review in" -> "in a review"
2) "and sent them" -> "and send them"
3) "I send him" -> "I sent him"
4) "I post it" -> "I posted it"
5) "I block out" -> "I blocked out"

"Bill's post" game score:
Anon1: 5
Rest of the world: 0

2. 6) "half of his age" -> "half his age"

"Bill's post" game score:
Anon1: 5
Rest of the world: 1

3. Just a nitpick:

Graph is Eulerian iff it's connected and at most two vertices have non-even degree.

4. I made all of the corrections from Anon1 and Anon2. Since the post is now better we are ALL winners!

Anon3- I thought a graph is Eulerian iff it has an Euler CYCLE and hence it needs all vertices to be of even degree. However, YES it has to be connected.
Will correct that later - need to log off soon since there is lightening in my area.

5. Lightning, unless it was simply getting brighter in your area.

We should play this game with Lance too, to be fair.

6. Have made the correction on Eulerian graph
theorem. Doubt it matters for NOW
since this post was a few days ago but
might matter for the future when they try to rebuild civilization from the only
remnant left:Complexity Blog.