push-down theorem on class numbers
As in the parent (http://planetmath.org/ClassNumberDivisibilityInExtensions) entry, given a number field , the class number
of is denoted by .
Theorem (Pushing-Down Theorem).
Let be a -extension of number fields and suppose that only one prime ideal of is ramified in and that this prime is totally ramified. Then implies .
References
- Fröh A. Fröhlich, On a method for the determination of class number factors in number fields, Mathematika, 4 (1957), 113-121.
- Iwas K. Iwasawa, A note on Class Numbers of Algebraic Number Fields, Abh. Math. Sem. Univ. Hamburg, 20 (1956), 257-258.