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bio website cs.ox.ac.uk/people/…
location Oxford, United Kingdom
age 51
visits member for 4 years, 8 months
seen 2 days ago

May
16
comment Extreme points of convex hull of Minkowski sum
@Cusp : if $Q$ is a point $a$ then $P+Q$ is just $P$ shifted by the vector $a$, and the vertices of $P+Q$ are the vertices of $P$ shifted by $a$, and this is what I claim.
May
16
comment Extreme points of convex hull of Minkowski sum
pictures speak for themselves here: en.wikipedia.org/wiki/Minkowski_addition
May
16
comment Extreme points of convex hull of Minkowski sum
@AnthonyQuas : this is also an exercise :-)
May
16
comment Extreme points of convex hull of Minkowski sum
$ext(P+Q)$ will be $conv(\{a_i+b_j\mid 1\leq i\leq p, 1\leq j\leq q\})$. It is an exercise.
May
15
reviewed Leave Open Splitting over infinite generated abelian subgroup?
May
14
answered Upper bound on Betti numbers of an intersection of hypersurfaces (or quadrics)
May
14
reviewed Approve Computing the centers of Apollonian Circle Packings
May
14
reviewed Approve A circle packing conjecture
May
14
reviewed Close Graded ring of a genus 2 curve
May
14
reviewed Leave Open Explanation of the definition of Saturated Sets in Lambda Calculus
May
12
reviewed Close Smallest sum of original column entries in 2d matrix
May
11
reviewed Close Representations of Hamilton's real/complex quaternions algebra
May
9
reviewed Leave Open Where to buy premium white chalk in the U.S., like they have at RIMS?
May
9
reviewed Close What are the applications of Voronoi diagrams in pure mathematics?
May
8
comment What is the complexity of intersecting two matrix algebras over a finite field?
The only hope seems to be to compute (partial) decompositions (using Meataxe, see e.g. homepages.warwick.ac.uk/~mareg/download/papers/bham_95/…) of the representations of the groups generated by $\mathcal{A}$ and $\mathcal{B}$, and hope they have small factors only. Then linear algebra becomes faster.
May
7
comment What is the complexity of intersecting two matrix algebras over a finite field?
Computational representation theory of groups is harder than linear algebra (this is a metatheorem :-)). My bet is that in general there cannot be a speedup hoped for in the question.
May
7
reviewed Close Representation Theory of Lie Groups: Reference Request
May
7
reviewed Close Backlund counting formula for Dirichlet L-functions?
May
7
reviewed Close cup-length of the first Chern class of complex grassmannian
May
5
reviewed Close If the quotient of an algebraic space $X$ by a finite group is a scheme, is $X$ a scheme?