# Monthly Archives: December 2010

## One Chance

I really liked this extremely short flash game. I felt touched by it, silly as it may sound. Advertisements

## On Norms

As everyone knows, norm is such a function  from the vector space  to , that Often you have a function, and you have to check whether it’s a norm or not. The first two conditions are usually easy to verify, but the … Continue reading

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## Triskaidekaphobia And You

Today Prof. K. told me that he considered 13 an unlucky number. He sounded only half joking. “You’re a mathematician, for —- sake, how can you say such nonsense!” – I wanted to shout at him, but instead I just … Continue reading

## Saddles, who needs them?

It is not difficult to prove that every continuously differentiable function : Must have a minumum point between two maximums and – If it has precisely one critical point, be it a local minimum or a local maximum, that point must also be a … Continue reading

## The Grandfather Of All Fractals And The Spikes Of Doom

This post is about the monster of the monsters, Riemann’s continuous almost nowhere differentiable function:   Proving that it is continuous is simple enough; proving that it doesn’t have the derivative almost everywhere is more complicated. (It is differentiable on a … Continue reading

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## Warming Up: Waves, Waves As Far As An Eye Can See

Here is a funny function that I could’t wrap my mind around as a freshman: if , and  . It is both ﻿﻿﻿﻿continuous and ﻿differentiable, the derivative at zero is 1, because: but at the same time – and that is … Continue reading