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location Oxford, United Kingdom
age 50
visits member for 3 years, 8 months
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Jun
17
comment Kneser graphs eigenvalues
as the eigenvalues and their multiplicities are known, this seems to be a straightforward exercise.
Jun
7
comment A semisimple group ring
perhaps you might want to edit the question to make it more "watertight"...
Jun
5
comment System of quadratic complex equations
Thank you - I actually published in computer algebra. I read the question as a request for a symbolic procedure...
Jun
4
comment System of quadratic complex equations
just as computer algebra systems do. E.g. by specifying Thom encoding, i.e. the signs of the derivatives at the root.
Jun
3
comment System of quadratic complex equations
the question explicitly says "without using a numerical method".
Jun
1
comment Elements of finite order of $\mathrm{PGL}(n,\mathbb{Q})$
there seems to be a lot known about finite subgroups of $GL_n(\mathbb{Q})$, cf. e.g. references in ams.org/journals/proc/1997-125-12/S0002-9939-97-04283-4/… E.g. each of them is conjugate to one in $GL_n(\mathbb{Z})$.
Jun
1
revised $LCM(q-1,\cdots,q^n-1)=q^{\frac{3}{\pi^2} n^2+o(n)}$
fixed typo in the subject line, making it nonsense
Jun
1
revised On the Positive Definiteness of a Linear Combination of Matrices
the previous editor removed that 0 there by mistake.
May
31
comment System of quadratic complex equations
the conditions $|x_k-1|\leq 1$ make this a system of quadratic equations and (quadratic) inequalities.
May
26
revised Solving a quadratic matrix equation with non-squared matrix
corrected nonsense
May
26
revised Solving a quadratic matrix equation with non-squared matrix
to address the changes in the question
May
26
answered Solving a quadratic matrix equation with non-squared matrix
May
26
comment What is the generic complexity of First Order Predicate Calculus?
I guess most of the people here, myself included, have no idea about generic complexity. Care to elaborate?
May
25
comment Existence of a real eigenvalue
it would help a lot if you spend few minutes typesetting entries in a readable way: e.g. the diagonal entry $M_{i+1,i+1}=1+4i-i^2-2n$ for all $i$ between 0 and $n-1$.
May
25
comment Correct spelling of names, Chebychev and Cholesky
@KConrad: as I used to speak reasonably good Dutch, I don't think I can be scared by phonetics any more. :-)
May
22
comment Correct spelling of names, Chebychev and Cholesky
Well, I can only say that English can't be a model example of "how to spell". It's more of "how to spell so that no-one without insider info will be able to pronounce correctly". :–)
May
22
answered Correct spelling of names, Chebychev and Cholesky
May
22
comment Correct spelling of names, Chebychev and Cholesky
there can't be any conclusive answer, as for different languages using Latin alphabet you get different spelling. In different times in Russia/USSR different rules regarding transliteration were in place; it used to be German, French, English (presently). Then there is a en.wikipedia.org/wiki/ISO_9 which stipulates the transliteration "Čebyšëv".
May
20
revised doubly-stochastic isomorphisms of graphs
added an explanation for Petersen graph
May
20
revised doubly-stochastic isomorphisms of graphs
corrected the definition of $A$