bio | website | cs.ox.ac.uk/people/… |
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location | Oxford, United Kingdom | |
age | 51 | |
visits | member for | 4 years, 4 months |
seen | 7 hours ago | |
stats | profile views | 2,091 |
Jan 30 |
comment |
How was Christoffel a 'whimsical eccentric'?
'die Theorie der Formen' probably meant algebraic geometry |
Jan 25 |
comment |
Cholesky decomposition of a positive semi-deﬁnite
how about ldl ? |
Jan 22 |
comment |
Binomial Identity
see e.g. the book "A=B": math.upenn.edu/~wilf/AeqB.html |
Jan 22 |
comment |
A determinant problem with symmetric PSD matrices
it is not advised to use lower case letters to denote matrices, especially if you use $I$ to denote the identity matrix, unless you want to confuse readers... |
Jan 22 |
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Cholesky decomposition of a positive semi-deﬁnite
en.m.wikipedia.org/wiki/Cholesky_decomposition has a proof that yes, indeed, it is correct, a p.s.d. R will have a Cholesky decomposition. |
Jan 21 |
comment |
A determinant problem with symmetric PSD matrices
$v_i v_i^H$ is of rank 1, i.e. all its eigenvalues except one are 0. |
Jan 21 |
comment |
Cholesky decomposition of a positive semi-deﬁnite
Do you mean to ask why R has a Cholesky decomposition if and only if R is positive semidefinite? |
Jan 20 |
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Cholesky decomposition of a positive semi-deﬁnite
"that how a positive semi-deﬁnite be done for Cholesky decomposition"??? What do you mean? English, please... |
Jan 3 |
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Can you efficiently solve a system of quadratic multivariate polynomials?
it is well-known that one can find representatives of connected components of real algebraic sets in $\mathbb{R}^n$ encoded by degree $d$ polynomials in $O(d)^{O(n)}$ ring operations. And $n$ in the exponent is not avoidable, generally speaking, unless P=NP. |
Jan 3 |
answered | Can you efficiently solve a system of quadratic multivariate polynomials? |
Jan 1 |
answered | Teaching homology via everyday examples |
Dec 7 |
comment |
Fubini for distributions which are not measures?
Do you mean to say we should look at the pushforward of $\Phi$ being a restriction to a sufficiently long interval in the subspace orthogonal to the (conjectural) support of $\mu$, and get a distribution with finite support? |
Dec 6 |
comment |
Fubini for distributions which are not measures?
Well, $F(u,v)$ is defined as above. It's an attempt to push a (combinatorial) setup which under some assumption was giving us measures, and everything was easy. Now we are trying to extend it further, and have this weirdness... |
Dec 6 |
revised |
Fubini for distributions which are not measures?
positive is not the right term here |
Dec 6 |
asked | Fubini for distributions which are not measures? |
Nov 29 |
comment |
About large z behavior of hypergeometric function $_2F_1(1/2,1/2,1;z)$
Did you try looking at standard sources on asymptotic expansions of integrals? It's probably doable by some standard technique. |
Nov 26 |
awarded | Yearling |
Oct 29 |
awarded | Popular Question |
Oct 11 |
comment |
How close to platonic can a non-platonic planar graph be?
You get quite a bit of constraints from Euler formula $v-e+f=2$: your graph is regular, i.e. $2e=vk$, and the $f-1$ faces are $\ell$-gonal, while the remaining face is $\ell'$-gonal. So this gives $2e=(f-1)\ell+\ell'$. Finally, don't forget topology, which forbids $\ell$ greater than 5... |
Oct 2 |
awarded | Caucus |