# Relations of p class groups on different layers of the 2 cyclotomic extension of CM number fields

### What is it about?

For odd primes there is a good notion how to define the minus part of the p class group of a CM number field. The classical definition fails for p=2. The aim of this paper is to give a definition of the minus part for p=2 and to establish properties known for odd primes for p=2 as well.

### Why is it important?

The paper shows that there is a definition of the minus part of the class group which is equivalent to the classical one in the case of odd primes. It could be tool to adopt proofs of results only known for odd primes for p=2 as well.

### Perspectives

The following have contributed to this page: Katharina Müller

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