Etale homotopy and sums-of-squares formulas
نویسندگان
چکیده
منابع مشابه
Etale Homotopy and Sums-of-squares Formulas
This paper uses a relative of BP -cohomology to prove a theorem in characteristic p algebra. Speci cally, we obtain some new necessary conditions for the existence of sums-of-squares formulas over elds of characteristic p > 2. These conditions were previously known in characteristic zero by results of Davis. Our proof uses a generalized etale cohomology theory called etale BP2.
متن کاملSums-of-Squares Formulas
The following is the extended version of my notes from my ATC talk given on June 4, 2014 at UCLA. I begin with a basic introduction to sums-of-squares formulas, and move on to giving motivation for studying these formulas and discussing some results about them over the reals. More recent techniques have made it possible to obtain similar results over arbitrary fields, and some of these are disc...
متن کاملAn Application of Hermitian K-Theory: Sums-of-Squares Formulas
By using Hermitian K-theory, we improve D. Dugger and D. Isaksen’s condition (some powers of 2 dividing some binomial coefficients) for the existence of sums-of-squares formulas. 2010 Mathematics Subject Classification: 19G38; 11E25; 15A63
متن کاملVerifying Nonlinear Real Formulas Via Sums of Squares
Techniques based on sums of squares appear promising as a general approach to the universal theory of reals with addition and multiplication, i.e. verifying Boolean combinations of equations and inequalities. A particularly attractive feature is that suitable ‘sum of squares’ certificates can be found by sophisticated numerical methods such as semidefinite programming, yet the actual verificati...
متن کاملEtale Realization on the A-homotopy Theory of Schemes
We compare Friedlander’s definition of étale homotopy for simplicial schemes to another definition involving homotopy colimits of pro-simplicial sets. This can be expressed as a notion of hypercover descent for étale homotopy. We use this result to construct a homotopy invariant functor from the category of simplicial presheaves on the étale site of schemes over S to the category of pro-spaces....
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
ژورنال
عنوان ژورنال: Mathematical Proceedings of the Cambridge Philosophical Society
سال: 2008
ISSN: 0305-0041,1469-8064
DOI: 10.1017/s0305004108001205