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location Oxford, United Kingdom
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visits member for 3 years, 4 months
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Sep
10
comment Main open computational problems in quantifier elimination?
I've expanded my answer to include more references. HTH.
Sep
10
revised Main open computational problems in quantifier elimination?
added stuff on SDP etc
Sep
8
answered Main open computational problems in quantifier elimination?
Sep
8
answered Binary codes with upper bound on pairwise distance
Sep
6
awarded  Nice Answer
Sep
5
comment Main open computational problems in quantifier elimination?
The problem of the current approach in this area is that in the simplest case of checking non-emptiness of a real algebraic set one ends up chasing roots of a univariate polynomial of degree at least the number of connected components of the set. An interesting topic might be to try to bridge it with the sums of squares-based methods in real algebraic geometry. (Which are in practice computationally more feasible, by using semidefinite programming). This of course opens a Pandora box of exactness etc...
Sep
4
comment Krull dimension and Morley rank
It's "Does X have property Y?" rather than your "Has X property Y?". The latter would be OK German grammar though :)
Sep
1
revised name for a polytope constructed from a system of linear equations?
added a possible way to approach the question
Aug
31
accepted centralizer of a n-cyclic permutation matrix over F_2 in GL(n,2)
Aug
31
asked name for a polytope constructed from a system of linear equations?
Aug
26
revised centralizer of the order 2^k cyclic permutation matrix over F_2
corrected the explanation of the formula, added a link
Aug
26
comment centralizer of the order 2^k cyclic permutation matrix over F_2
oops, indeed, the formula I gave is for the quotient of the centralizer over $\mathbb{Z}/2^k\mathbb{Z}$. I'll update the body of the question.
Aug
26
answered A moment problem on $[0,1]$ in which infinitely many moments are equal
Aug
26
comment What is the sandpile torsor?
and how about Eulerian digraphs? In this case the question about the torsor makes perfect sense too.
Aug
24
comment centralizer of the order 2^k cyclic permutation matrix over F_2
here I asked a more general question: mathoverflow.net/questions/140280/…
Aug
24
asked centralizer of a n-cyclic permutation matrix over F_2 in GL(n,2)
Aug
21
comment Infinite quotient of Hurwitz Group
if you know that there is a central element of order 2 then you know that there is a proper infinite quotient group...
Aug
21
comment Solving a System of Quadratic Equations
do you talk about real solutions only?
Aug
19
comment centralizer of the order 2^k cyclic permutation matrix over F_2
Murray's paper doesn't really give you a closed form answer, as far as I can see, but Prop. XI(5.7) of Bass indeed does. I wonder if the more general case of $2^km$-cycle, for $m$ odd, has been done before (We also have a result for this case too).
Aug
18
comment Finding all local maximum points of a function?
certainly, $x=(a,\dots,a)$ is a global maximum for any $a$, not only for $a=0$.