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location  Oxford, United Kingdom  
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14h

comment 
Irreducibility of a polynomial
oops, sorry, voted to reopen. 
16h

comment 
Can all unitdistance graphs have their vertices at algebraic integers?
@Ilya: ah, right. And not only into a 6wheel, but any subgraph of the hexagonal lattice. I wonder if this is the complete answer. 
17h

comment 
Can all unitdistance graphs have their vertices at algebraic integers?
@Ilya: good point. This means that $G$'s with a homomorphisms to 6cycle is a good class, in terms of the original question. (No idea why such graphs are interesting though) :) 
18h

revised 
Largest eigenvalue adjacency matrixlink deletion
typo fixed 
21h

comment 
Can all unitdistance graphs have their vertices at algebraic integers?
How about adding a bit of intuition, say do you know such $f$ for the triangle? (and if yes, then one immediately has $f$ for the 3colourable graphs). 
1d

comment 
When can the group of permutations generated by the translations of a group be identical with the group of all permutations on this group?
en.wikipedia.org/wiki/Cayley%27s_theorem ? 
1d

revised 
Can every finite abelian $p$group with duality pairing be written as cokernel of a symmetric matrix over the $p$adic integers?
edited title 
2d

comment 
Can a graph be reconstructed from its cycle lengths?
It seems that if you know this sequence and the adjacency matrix of the graph, then you can compute the matching polynomial, which is #Pcomplete. 
Jan 23 
comment 
Open access journals in number theory
IMHO a publication of a close to final version on arxiv.org is good enough for all practical purposes. 
Jan 23 
comment 
accelerate convex optimization by proximal projection
can't you just stop your quadratic optimisations early? 
Jan 23 
comment 
research on the structure/properties of permutation matrix/table with $(i,j)th$ entry as $\pi_j\circ \pi_i^{1}$
it's not clear what kind of order on permutations you are talking about, and, indeed, what the entries of these tables are. 
Jan 18 
comment 
When is edge colored circulant isomorphism polynomial?
@joro  sure, they use the definition I mentioned, too. 
Jan 18 
comment 
When is edge colored circulant isomorphism polynomial?
In your reduction attempt, you lose the needed automorphisms, so it does not work. 
Jan 18 
comment 
When is edge colored circulant isomorphism polynomial?
Edgecoloured circulant graphs are edgecoloured graphs admitting a cyclic transitive automorphism group. Colouring here is just a map from a set of colours to the edges. 
Jan 18 
reviewed  Approve SaitoWright definition of Rickart C*algebras 
Jan 18 
comment 
Minimally intersecting subsets of fixed size
to generalise my example to another small $k$, take a the affine space of bigger dimension; in more generality, you can play with putting together different 2designs with appropriate parameters. 
Jan 18 
comment 
Minimally intersecting subsets of fixed size
generalising for arbitrary $k$ is hard, as optimal codes are in general not known. 
Jan 16 
comment 
Minimally intersecting subsets of fixed size
@Bill  I added a possible construction to my answer. 
Jan 16 
revised 
Minimally intersecting subsets of fixed size
answering a question from the comment 
Jan 16 
comment 
Does anyone know this determinant?
So you have a complete graph with edges weighted in Hankel matrixlike fashion, and then you take the "unsigned Laplacian" matrix of this (weighted) graph. Hmm... 