Ramification Groups of Local Fields with Imperfect Residue Class Fields Original Research Article

The Galois group of a Galois extension of local fields with an inseparable residue class field extension has two intertwined filtrations with ramification groups. This note contains some elementary results on the structure of these filtrations, that are similar to those given by J.-P. Serre in "Corps Locaux," Chap. IV, Sect. 2 (Hermann, Paris, 1962), for the case that the residue class field extension is separable.