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bio website tx.technion.ac.il/~felixg/…
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age 31
visits member for 3 years, 1 month
seen Apr 14 at 0:34

Apr
5
comment Does this inequality always hold?
So, what is the motivation/context for this conjecture?
Apr
1
comment How large can a set of nearly equidistant points be?
@BenoîtKloeckner I am more interested in $\epsilon>\frac{1}{n-1}$ and fixed.
Apr
1
revised How large can a set of nearly equidistant points be?
edited title
Apr
1
comment How large can a set of nearly equidistant points be?
@BillJohnson JL says that if I have such a set in a higher dimension $n \approx e^{k}$ , then I can embed it into $\mathbb{R}^{k}$ while (almost) preserving the distance property. But I don't see how it guarantees the existence of such a set to begin with. Am I missing something here? P.S. JL does not assume anything on the relation of the pairwise distances to each other, while in this case I need to. P.P.S. The question actually originates in an attempt to understand a result related to JL. :)
Apr
1
asked How large can a set of nearly equidistant points be?
Mar
28
comment What are the external triumphs of matroid theory?
Can you share it now...?
Mar
16
asked power laws emerging from the sandpile model
Mar
10
awarded  Yearling
Feb
25
comment When does a d.r.v. take a value very close to the mean?
@Suvrit Yes, sort of. These are the volumes of all $n \times k$ submatrices of a fixed $n \times m$ matrix.
Feb
25
asked When does a d.r.v. take a value very close to the mean?
Feb
4
awarded  Notable Question
Feb
3
comment Rank changes with matrix edits
@Turbo Yes, I think it does.
Feb
3
comment Rank changes with matrix edits
@Turbo In that case, things are open again.... :( If you want to discuss the specific case, feel free to email me.
Feb
3
comment Rank changes with matrix edits
@Turbo Yes, all you need is Hermitianness of $M$ and $W$. But as I said, having $\{0,1\}$ helps to perhaps pinpoint precisely which of the three cases occurs.
Feb
3
comment Rank changes with matrix edits
@Turbo The magic works because it's a rank 1 update. It's possible to use interlacing for rank $k$ updates, but the bounds get progressively weaker, of course. The proof for rank $k$ is just an inductive application of Corollary 4.3.9 $k$ times (decompose $W$ as the sum of $k$ matrices of rank $1$).
Feb
3
comment Rank changes with matrix edits
@Turbo It's proved in the reference I gave (the standard one on the subject).
Feb
3
comment Rank changes with matrix edits
Btw, why the extremal-combinatorics tag? Is there an interesting application you have in mind?
Feb
3
answered Rank changes with matrix edits
Feb
2
revised An exact fraction of a matrix
edited body
Feb
2
comment An exact fraction of a matrix
@AllenKnutson $M$ is $A$. Fixing now, Thanks.