symmetric monoidal (∞,1)-category of spectra
For the endomorphism of powering by on the multiplicative group over an étale site, then if is invertible over the site then there is a short exact sequence
where is the group of units of order , the group of th roots of unity.
This is called the Kummer sequence.
The analog for the additive group is the Artin-Schreier sequence. Both are unified in the Kummer-Artin-Schreier-Witt exact sequence.
Named after Ernst Kummer.
Günter Tamme, section II 4.4 of Introduction to Étale Cohomology
Jordan Watts, The Kummer sequence (pdf)
Max Lieblich, around prop. 2.3.4.4 Moduli of twisted sheaves (arXiv:math/0411337)
Last revised on May 26, 2014 at 06:38:09. See the history of this page for a list of all contributions to it.