In
mathematics
Mathematics is an area of knowledge that includes the topics of numbers, formulas and related structures, shapes and the spaces in which they are contained, and quantities and their changes. These topics are represented in modern mathematics ...
, the Milnor conjecture was a proposal by of a description of the
Milnor K-theory (mod 2) of a general
field ''F'' with
characteristic different from 2, by means of the
Galois (or equivalently
étale) cohomology of ''F'' with coefficients in Z/2Z. It was proved by .
Statement
Let ''F'' be a field of characteristic different from 2. Then there is an
isomorphism
:
for all ''n'' ≥ 0, where ''K
M'' denotes the
Milnor ring
In mathematics, Milnor K-theory is an algebraic invariant (denoted K_*(F) for a field F) defined by as an attempt to study higher algebraic K-theory in the special case of fields. It was hoped this would help illuminate the structure for algebr ...
.
About the proof
The proof of this theorem by
Vladimir Voevodsky uses several ideas developed by Voevodsky,
Alexander Merkurjev,
Andrei Suslin,
Markus Rost,
Fabien Morel
Fabien Morel (born 22 January 1965, in Reims) is a French algebraic geometer and key developer of A¹ homotopy theory with Vladimir Voevodsky. Among his accomplishments is the proof of the Friedlander conjecture, and the proof of the complex cas ...
,
Eric Friedlander, and others, including the newly minted theory of
motivic cohomology (a kind of substitute for
singular cohomology for
algebraic varieties) and the
motivic Steenrod algebra.
Generalizations
The analogue of this result for
primes other than 2 was known as the
Bloch–Kato conjecture. Work of Voevodsky and
Markus Rost yielded a complete proof of this conjecture in 2009; the result is now called the
norm residue isomorphism theorem.
References
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Further reading
* {{citation , last=Kahn , first=Bruno , chapter=La conjecture de Milnor (d'après V. Voevodsky) , language=French , editor1-last=Friedlander , editor1-first=Eric M. , editor2-last=Grayson , editor2-first=D.R. , title=Handbook of ''K''-theory , volume=2 , pages=1105–1149 , publisher=
Springer-Verlag , year=2005 , isbn=3-540-23019-X , zbl=1101.19001
K-theory
Conjectures that have been proved
Theorems in algebraic topology