4,069 reputation
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bio website cs.ox.ac.uk/people/…
location Oxford, United Kingdom
age 50
visits member for 3 years, 11 months
seen 36 mins ago

Oct
1
revised Regular graphs with strongly regular edge colorings
more info added
Oct
1
revised Regular graphs with strongly regular edge colorings
deleted 12 characters in body
Oct
1
answered Regular graphs with strongly regular edge colorings
Sep
30
awarded  Explainer
Sep
25
comment pencil of quadrics consisting of singular quadrics
it is essentially about pencils of matrices $A_q$, with $q(x)=x^\top A_q x$. Probably you can only find this in solution sheets to some course or textbook...
Sep
25
comment Optimization problem involving an entrywise function
and of course if you do not say anything about $\phi$ then it looks pretty hopeless,
Sep
25
comment Optimization problem involving an entrywise function
note that $X^\top\Sigma X$ need not be invertible.
Sep
24
revised Hilbert's Theorem on $L_2$ norm of polynomials in $\mathbb{Z}[X]$ - Explicit construction and a converse?
typo in the year
Sep
24
comment Conjectured integral for Catalan's constant
can you rewrite your last integral in terms of functions of a real variable?
Sep
23
comment nonnegativity conditions for a polynomial in two variables
for more variables nothing of this sort is known; Hilbert's (1893) paper substantially uses quite tricky algebraic geometry of complex plane curves (something that nowadays one would explain using en.wikipedia.org/wiki/Theta_characteristic)
Sep
23
comment nonnegativity conditions for a polynomial in two variables
for bivariate polynomials the much better route is outlined in my answer.
Sep
22
revised nonnegativity conditions for a polynomial in two variables
more references, and an explanation
Sep
22
answered nonnegativity conditions for a polynomial in two variables
Sep
22
comment Complexity of Untwisting Polygons
generating random polygons is a different story then; they care about the uniformity, etc...
Sep
22
comment Complexity of Untwisting Polygons
I'm not sure it's not better to forget all the edges and just construct a polygon directly.
Sep
22
awarded  Custodian
Sep
22
reviewed Close Algorithm to find the “optimal” path in a given graph
Sep
22
reviewed Approve suggested edit on Non-trivial bounds for polynomials at a fixed point
Sep
22
answered Complexity of Untwisting Polygons
Sep
20
reviewed Approve suggested edit on Changing Left Comodules into Right Comodules via the Antipode, and Comodule Tensor Products