Submission: 2012, Dec 29
In this paper we define a notion of Witt group for sesquilinear forms in hermitian categories, which in turn provides a notion of Witt group for sesquilinear forms over rings with involution. We also study the extension of scalars for $K$-linear hermitian categories, where $K$ is a field of characteristic $\neq 2$. We finally extend several results concerning sesquilinear forms to the setting of systems of such forms.
2010 Mathematics Subject Classification: 11E39, 11E81
Keywords and Phrases: sesquilinear forms, hermitian forms, systems of sesquilinear forms, hermitian categories, $K$-linear categories, scalar extension, Witt group.
Full text: dvi.gz 27 k, dvi 68 k, ps.gz 761 k, pdf.gz 146 k, pdf 168 k.