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Jan
24
comment What is a good introduction to cluster algebras from surfaces?
I should point out the canonical source for sources on cluster algebras: Fomin's "Cluster algebras portal", math.lsa.umich.edu/~fomin/cluster.html
Jan
22
comment What is a good introduction to cluster algebras from surfaces?
@TomCopeland Thank you for reminding me about Lauren's notes, arxiv.org/abs/1212.6263 ! They seem to cover exactly what I wanted. If you make that an answer, I will accept it.
Jan
20
comment What is a good introduction to cluster algebras from surfaces?
@JanGrabowski, thanks for pointing out Schiffler's notes, which I was unfamiliar with, and which may come in handy (but for the same reason as for the Schiffler paper Tom suggested, are not really what this question is asking for).
Jan
20
comment What is a good introduction to cluster algebras from surfaces?
All suggestions are welcome, but in the interests of clarifying my question, I'll explain why Tom and Jan's suggestions aren't quite what I'm looking for. Tom's suggestion (a paper by Schiffler) doesn't have any Teichmuller theory at all, and what I really want is a straightforward explanation of the link to Teichmuller theory (interpreting cluster variables as lambda-lengths, etc.). Jan's suggestion (plus its sequel by Fomin-Thurston) are canonical sources, but I was hoping for something easier for a student to read, and which devotes less of its energy to the punctured case.
Jan
19
comment What is a good introduction to cluster algebras from surfaces?
@darijgrinberg Gekhtman-Shapiro-Vainshtein takes a Poisson geometry approach, which is great, but I would like something more direct if possible. (Though maybe what I want can be found in there.) If you post a more specific question about "the algebraic and combinatorial parts", I may be able to help. Have you seen the notes from Fomin's Park City course, written up by Nathan Reading (arXiv:math/0505518)?
Jan
19
asked What is a good introduction to cluster algebras from surfaces?
Jan
2
awarded  Civic Duty
Dec
18
reviewed Approve Rooks in three dimensions
Dec
18
comment On understanding Orlov's LG B model
Lemma 3.6 of what? (A link would be best.)
Dec
5
comment Find m most distant points from a set of n points
An alternative to the strategy the OP proposes would be to find the minimal distance between a pair of points in the set, and discard one of those points, and repeat until only m points remain. The time would be quadratic, but I guess the outcome would be better than with the algorithm the OP proposes.
Dec
5
comment Find m most distant points from a set of n points
This question uses a lot of terms which are unfamiliar to me and which I think might also be unfamiliar to other people in this forum who might still be interested in this question (as I am). What is SE(3)? What is a kd-tree? What is 6-DOF? You also still haven't said what you want to maximize: is it the minimum over all pairs of the pairwise distances among your points, or some other function of the distances?
Nov
18
comment Decomposing polyhedral cones into “direct sums” and a polynomial
Is the sum of the $d_i$ anything nice? (That would be the multiplicity of the root 1, of course.)
Nov
14
comment Regular unimodular triangulation for a certain simplex
I think the question as stated is a perfectly good question, so I would be in favour of not deleting it. I would also be interested in knowing what question you meant to ask, though I guess it should be a separate question. Also (though this may become clear when I know what question you were answering) it isn't clear to me why the triangulation you give in your answer is automatically regular.
Nov
14
comment Regular unimodular triangulation for a certain simplex
This doesn't seem right to me. What if the vertices are (0,0), (0,2), and (3,2)? The edge joining (0,0) to (3,2) is not an intersection of lines such as you describe.
Nov
13
answered Positivity of Ehrhart polynomial coefficients
Oct
16
awarded  Yearling
Oct
1
comment ellipsoids have spherical section
In case it wasn't clear from Ryan's comment, in the 3-d case, there is one condition which involves $x_1$ and $x_3$. One linear condition in $\mathbb R^3$ defines a plane. In this case, as Ryan pointed out, a plane containing the $x_2$-axis.
Sep
4
reviewed Approve Computing the q-series of the j-invariant
Sep
3
reviewed Approve Injective dimension of graded-injective modules
Aug
21
revised abstract-polytopes wiki description
fixed typo in what I wrote