The sphere spectrum
BID, Lisboa 2017
  1. Extensions of number systems
2. Negative numbers
3. Briefly on sheep
4. A trade deficit
5. Out in space
6. Ulla and Henriette live in RP
7. Negative sets
8. The sphere spectrum
9. Brave New World

Extensions of number systems

We are used to extensions of number systems
Z <Q <R <C.
These number systems are created by adding solutions to increasingly more complicated questions. Today, we're going in the opposite direction: there are number systems more fundamental than Z. This number scheme contains more concrete information, and hence manipulations become more involved, but encodes problems the integers hardly can speak about.

In order to do this, I must speak about negative sets (and negative dimensional vector spaces?)

Negative numbers
Bjørn Ian Dundas
2017-07-21 14:40:56 UTC