On the separation of connected components by étale cohomology
In this paper a new proof that for any connected component \(C\) of the real spectrum of a ring, it is possible to find a cohomology class whose signature separates \(C\) from its complement is given (former proofs had been given by Colliot-Thélène and Parimala, Buresi and Scheiderer). The new proof follows the pattern of the proof formerly given by Mahé for the separation of connected components by quadratic forms, making thus the analogy between the two situations more clear.
connected component of real spectrum of ring
scientific article; zbMATH DE number 827891