2,318 reputation
1820
bio website web.mat.bham.ac.uk/~barberba
location Birmingham, UK
age
visits member for 3 years, 1 month
seen 4 hours ago

Postdoc in Birmingham with Daniela Kühn.


1d
reviewed No Action Needed Kan extensions of pseudofunctors
Aug
30
comment What characteristic of a graph depend on the vertex labeling?
People have looked at Ramsey theory for graphs with an ordering of their vertices, although this is more looking at a new class of objects than a property of graphs that depends on some choice of vertex ordering.
Aug
30
reviewed No Action Needed Can we drop commutativity assumption?
Aug
30
reviewed No Action Needed Intuition for the tensor algebra?
Aug
24
reviewed Close Annihilators of elements in symmetric algebras
Aug
23
comment Can every permutation group be realized as the automorphism group of a graph (acting on a subset of the vertices)?
Here's an extremely similar construction that no longer merits its own answer. As usual I'll state the labelled version. Start with the full Cayley graph $\Gamma$ of $P$; $P$ acts on $V(\Gamma) = P$ by $\pi(\rho) = \pi \rho$. Form the complete bipartite graph between $P$ and $X$. The group action has to be encoded somewhere, so label each edge $(\pi, x)$ by $\pi^{-1}(x)$. I think that this works as required. It would be very interesting to see a construction that does not essentially pass through the Cayley graph.
Aug
23
reviewed Approve Does every manifold have a flat connection?
Aug
23
reviewed Reject Catalan numbers as sums of squares of numbers in the rows of the Catalan triangle - is there a combinatorial explanation?
Aug
20
comment Area defined with $\pm$ closedness
@KevinP.Costello Perhaps there is no point at maximal distance from the origin?
Aug
17
reviewed No Action Needed Largest eigenvalues distribution of tridiagonal symmetric random matrix
Aug
17
comment Can we estimate the probability $\mathbf{P}(a-k|a - b) $ on a random graph?
Do you know anything about the values of the $p_{uv}$? This is likely to be extremely difficult in full generality, but straightforward for many particular examples. For instance, if the $p_{uv}$ are constant and $|G|$ is large then all of your expressions are approximately equal to $1$ as $G$ is very likely to be connected.
Aug
17
reviewed No Action Needed Gagliardo Nirenberg inequality for the laplacian
Aug
17
reviewed Approve Gagliardo Nirenberg inequality for the laplacian
Aug
14
reviewed No Action Needed Is there any theory of Hamilton-Jacobi system?
Aug
13
comment Maximal Number of Pairs of Orthogonal vectors in a set of $n$ vectors in $\mathbb{R}^3$
Following the comments, perhaps you could clarify whether or not the pairs are ordered?
Aug
12
comment Kissing number and overlapping number
Is it obvious that the overlapping number cannot exceed the kissing number no matter how strange the family $S$?
Aug
12
reviewed No Action Needed How can I show that “almost all function” have property P?
Aug
11
reviewed Reviewed A problem upon function series
Aug
8
awarded  co.combinatorics
Aug
4
reviewed No Action Needed Quadratic variation for discrete Martingale