### Top Posts

### Recent comments

- Tim Penttila on A rant
- Tim Penttila on A rant
- Peter Cameron on A rant
- Dima on Oligomorphic groups: topology or geometry?
- G. Smith on The symmetric group, 1

### Blogroll

- Astronomy Picture of the Day
- Azimuth
- British Combinatorial Committee
- Comfortably numbered
- Diamond Geezer
- Exploring East London
- From hill to sea
- Gödel's lost letter and P=NP
- Gil Kalai
- Jane's London
- Jon Awbrey
- Kourovka Notebook
- LMS blogs page
- Log24
- London Algebra Colloquium
- London Reconnections
- MathBlogging
- Micromath
- Neill Cameron
- neverendingbooks
- Noncommutative geometry
- numericana hall of fame
- Ratio bound
- Robert A. Wilson's blog
- Since it is not …
- Spitalfields life
- Sylvy's mathsy blog
- SymOmega
- Terry Tao
- The Aperiodical
- The De Morgan Journal
- The ICA
- The London column
- The Lumber Room
- The matroid union
- Theorem of the day
- Tim Gowers
- XKCD

### Find me on the web

### Cameron Counts: RSS feeds

### Meta

# Tag Archives: generalized line graphs

## The ADE affair, 5

A root system is a finite set S of vectors in Euclidean space with the properties If s,λs∈S, then λ=±1. The set S is mapped to itself by the reflection in the hyperplane perpendicular to each element s of S. … Continue reading

Posted in exposition
Tagged Coxeter group, generalized line graphs, line graph, root systems, Whitney's theorem
2 Comments

## The ADE affair, 1

In the 1970s, the American Mathematical Society held a symposium on Mathematical developments arising from Hilbert problems. Each of Hilbert’s problems was described, and subsequent progress and developments traced, by at least one expert in the area. As part of … Continue reading

Posted in exposition, history
Tagged Coxeter diagrams, Dynkin diagrams, generalized line graphs, Hilbert problems, root systems
1 Comment