Multiplicativity of Ramification Index

Stream: Is there code for X?

[Junjie Bai]

Has anyone proof that the multiplicativity of ramification index? If L/K'/K is Galois extension tower, then e(L/K) = e(L/K') * e (K'/K)?

[Kenny Lau]

@Junjie Bai I just copied "multiplicativity of ramification index" to https://leansearch.net/?q=+multiplicativity+of+ramification+index and then the first result was correct

[Junjie Bai]

Thanks a lot!

[Kevin Buzzard]

FLT has the result that the global e is also the change in the valuation corresponding to the prime ideal, from which this easily follows.

[Junjie Bai]

Thank you! That helps!