A method is described for improving the sensitivity of peptide mapping with electrospray liquid chromatography--mass spectrometry using trifluoroacetic acid (TFA) containing HPLC mobile phases. Theâ€¦ (More)

We classify all possible extensions of a valuation from a ground field K to a rational function field in one or several variables over K. We determine which value groups and residue fields canâ€¦ (More)

We give a criterion for maps on ultrametric spaces to be surjective and to preserve spherical completeness. We show how Henselâ€™s Lemma and the multidimensional Henselâ€™s Lemma follow from our result.â€¦ (More)

In spite of the analogies between Qp and Fp((t)) which became evident through the work of Ax and Kochen, an adaptation of the complete recursive axiom system given by them for Qp to the case ofâ€¦ (More)

In this paper, we consider the defect (also called ramification deficiency) of finite extensions of valued fields. For a valued field (K, v), we will denote its value group by vK and its residueâ€¦ (More)

We consider the Zariski space of all places of an algebraic function field F |K of arbitrary characteristic and investigate its structure by means of its patch topology. We show that certain sets ofâ€¦ (More)

We explain how to compute in the algebraic closure of a valued field. These computations heavily rely on the Newton Polygon Algorithm. They are made in the same spirit as the dynamic algebraicâ€¦ (More)

We give a criterion for maps on ultrametric spaces to be surjective and to preserve spherical completeness. We show how Hensel's Lemma and the multi-dimensional Newton's Lemma follow from our result.â€¦ (More)

We show that every henselian valued field L of residue characteristic 0 admits a proper subfield K which is dense in L. We present conditions under which this can be taken such that L|K isâ€¦ (More)