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CATEGORIES:Algebra Seminar
SUMMARY:Additive group invariants in positive characterist
ic - Emilie Dufresne\, Universität Heidelberg
DTSTART:20100409T150000Z
DTEND:20100409T160000Z
UID:TALK2644AT
URL:/talk/index/2644
DESCRIPTION:Additive group actions in positive characteristic
Abstract: (joint work with Andreas Maurischat) Rob
erts\, Freudenburg\, and Daigle and Freudenburg ha
ve given the smallest counterexamples to Hilbert's
fourteenth problem. Each arises as the ring of in
variants of an additive group action on a polynomi
al ring over a field of characteristic zero\, and
thus\, each corresponds to the kernel of a locally
nilpotent derivation. In positive characteristic\
, additive group actions correspond to locally fin
ite iterative higher derivations\, a more restrict
ive notion. We set up characteristic-free analogs
of the three examples mentioned above\, and show t
hat\, contrary to characteristic zero\, in every p
ositive characteristic\, the invariant rings are f
initely generated.
LOCATION:Watson Building\, Lecture Room A
CONTACT:David Craven
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