# Category Archives: Geometry/Topology

## Can computers write proofs

that human being can understand? By that I mean not those formal logic nonsense. Tim Gowers is doing an interesting experiment to get readers to judge proofs of exercises in metric space theory. The three proofs are supposed to be … Continue reading

## Geometry Puzzle

A neat little puzzle from John Mason. How are the blue and red area related?

## Nice geometry problem

From the MAA minute math! a problem on 3d geometry. I must confess I peeped at the hint.

## A matter of perspective

Have you ever watched rugby matches on TV and noticed the advertisements on the field that looked 3-dimensional? I remember having the impression that the adverts were superimposed by the TV people. But when I told the wife, she plainly … Continue reading

Posted in Applications, Books, Geometry/Topology | 1 Comment

## Soap bubbles and current research

That’s the title of Frank Morgan’s talk today. The main takeaway is how, (motivated?) students can be exposed to interesting problems and work on current research. For example, it has been known for almost 2000 years that the circle in … Continue reading

## MAA and applications of topology

I used to be a member of MAA but found that it did nothing much for me except I get to issues of American Mathematical Monthly. I would classify that as good to have – something to read when I … Continue reading

## Origami and Mathematics

Recently I had the horrendous realization that I’ve lost whatever little origami skills that I once possessed. I was trying to entertain a bored child on the plane who speaks a little English, and I knew no German save “guten … Continue reading

## Picture Hanging Puzzle

Just attended a nice talk by Erik Demaine on Origami and puzzles. He demonstrated some remarkable stuff and ended with a cute picture hanging puzzle – how to hang a puzzle with two nails such that by removing either one, … Continue reading

Posted in Fun Stuff, Geometry/Topology | 1 Comment

## How Did Escher Do It

I’ve always loved Escher’s circle limit. Here’s a neat article attempting to reconstruct it.

## Klein Bottle Opener

How cool is that! http://www.bathsheba.com/math/klein/klein_x1.html \$78 though.

## Finite Projective Plane

Learned a cool trick today. The finite projective plane of order n has $n^2 + n + 1$ points, $n^2 + n + 1$ lines, $n + 1$ points on each line, $n + 1$ lines passing each point. The … Continue reading

## One down, six more to go

The first of the 7 Clay milliennium prize has been awarded. Sure it was a controversial one, but I guess it was fitting that the winner was one who didn’t want the million bucks. Money is not the ultimate prize … Continue reading

## Bach’s canon on a moebius strip

From boing boing, exactly what the title says.

## Euler’s Rotation theorem in 3D

Any rigid body displacement where a point is fixed is equivalent to a rotation. I saw this neat proof from Don Koks’ Explorations in Mathematical Physics. By the hypothesis [tex] |Ar| = |r| \implies r^t A^t A r = r^t … Continue reading

Posted in Books, Geometry/Topology, Linear Algebra | 1 Comment

## Ipod and the Golden Ratio

I gave a talk before on the golden ratio, so when I came across this blog entry Ipod and the golden ratio via Gooseania, I quickly saved this link in case I have to give the same talk again.

## The Four Pillars of Geometry

By John Stillwell. I picked this up from the new arrivals counter at the library. The hyperbolic tessellation on the front cover was invitation enough for me. The book is about teaching geometry to undergrads from four different perspectives: 1) … Continue reading