# All Questions

**0**

votes

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4 views

### Pseudodifferential operators on compact manifolds with boundary

I have heard that the square root of the Dirichlet (or the Neumann) Laplacian is not a pseudodifferential operator on compact manifolds with boundary. The context in which this was said was that ...

**0**

votes

**0**answers

13 views

### A question about Asaaf Naor's review in Bourbaki about the Batson-Spielman-Srivastava result

I am referring to this article - http://www.cims.nyu.edu/~naor/homepage%20files/Exp.1033.pdf
If I understand right, the author states that his equations (8) and (9) are equivalent to the equations ...

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votes

**0**answers

29 views

### Expectation of product of cosines

I posted this question on math.stackexchange (under the same title), but it has not received any answers. It is possibly more appropriate here in any case.
I am reading a paper that starts with
$$
...

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votes

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16 views

### Books on First Hitting times

I am looking for books or expositional papers on First hitting times of sets by Brownian motion (any dimension).
Here are some that are devoted to this subject or contain sections on it:
1)Sidney ...

**1**

vote

**0**answers

29 views

### Generators of the algebra of invariant polynomials on a Lie algebra and the root-space decomposition

Let $G$ be a connected, simply-connected complex semisimple group with Lie algebra $\mathfrak{g}$. Fix a pair $T\subseteq B\subseteq G$ of a maximal torus and Borel subgroup, and let $\mathfrak{t}$ ...

**4**

votes

**2**answers

98 views

### How many isolated roots can a polynomial in $z$ and $\overline{z}$ have?

This is probably well-known by I can't find it now online. My guess is that if the degree is $n$ then it's $2n$ but it's just a hunch.
EDIT:
This is an edited version. Before I asked about roots ...

**-1**

votes

**0**answers

26 views

### question related to kernel methods [on hold]

i have some questions related to kernel methods in Machine Learning,hope someone can give proves. K(x,y) is kernel iff 1.K is symmetric 2.K is positive definite. ...

**2**

votes

**0**answers

36 views

### Meaning of eigenvalue 1 and symmetry in Laplacian spectra of graphs

We often see normalized Laplacian spectra of graphs where density on eigenvalue 1 serves as an axis of symmetry, with particularly high (blue spectra in the figure) or low densities (red spectrum) ...

**1**

vote

**0**answers

53 views

### state-of-the-art graph theory libraries like LEDA

I came across LEDA (library of efficient data types and algorithms) which implements graph theory algorithms:
http://www3.cs.stonybrook.edu/~algorith/implement/LEDA/implement.shtml
I want to ask: ...

**4**

votes

**0**answers

118 views

### The zeta function and classical mechanics

In this paper, Guilherme França and André LeClair show that $$\gamma\sim 2 \pi \left(y-11/8\right)/W\left((y-11/8)e^{-1}\right)$$ where $W$ is the Lambert W function, and $\gamma$ are imaginary parts ...

**-1**

votes

**0**answers

21 views

### Using Excel's NormInv and Proportion Estimates for Monte Carlo [on hold]

I have some data.
Here's an example (ogive)
517
625
813
855
966
1143
1227
1248
1343
1367
1461
1465
1572
1574
1738
I can derive a % based on frequency of the value
0
0.071428571
0.142857143
...

**2**

votes

**0**answers

45 views

### Effective version of the Bombieri-Vinogradov theorem

Is there an effective version of the Bombieri-Vinogradov Theorem, in that have bounds on the implied constant been found?

**2**

votes

**1**answer

114 views

### Is this inequality true?

Let $\Omega$ be a bounded domain with smooth boundary. Let $$ S=\{u\in C^2(\overline \Omega): \frac{\partial u}{\partial n}=0 \text{ on } \partial\Omega \}.$$ Fix $\Phi\in S$ with $\Phi(x)>0$ for ...

**1**

vote

**0**answers

34 views

### A (different) foliation arising from Hopf fibration

In this question, first we fix an isomorphism between $TS^{3}$ and $S^{3}\times \mathbb{R}^{3}$.(To be more precise we consider the global trivialization of $TS^{3}$ with help of $3$ global ...

**4**

votes

**0**answers

93 views

### Is there a simple proof that Milnor $K_2$ of a number field is torsion?

This is a theorem of Garland. I had a look at the original paper which looks pretty complicated. I was wondering if the proof has been simplified over the years or if a different approach is nowadays ...

**2**

votes

**1**answer

32 views

### Minimum degree of rational form

Given a positive integer $g$, what is the minimum degree of the rational function that represents the real function $P(x)$ where $P(x)=\frac{x- x\mod g}{g}+1$ at $x \in ...

**1**

vote

**0**answers

52 views

### Certain algebraic variete defining by multiplicative functional equation

In this question $B(M_{n}(\mathbb{C}))$ and $B^{2}(M_{n}(\mathbb{C}))$ are the linear space of all linear and 2-linear $M_{n}(\mathbb{C})$-valued maps on $M_{n}(\mathbb{C})$, respectively. ...

**0**

votes

**0**answers

17 views

### Minimum degree rational function interpolation

Find a rational function $R(x)$ such that:
$1)$ For $i\in\{1,\dots,g\}$, $x_{i}=x_{i-1}+g$ with $x_0=0$.
$2)$ For $i\in\{0,\dots,g-1\}$ $R(x_i)=R(x_i+1)=\dots=R(x_i+g-1)=i+1$.
$3)$ $R(x_g)=g+1$.
...

**0**

votes

**2**answers

30 views

### Generalised “projection” of a metric space

Assume we have $n$ points $p_0\ldots p_{n-1}$ which form a discrete metric space $V$ with metric $d$. Can we define a function $f:V\rightarrow \mathbb{R}$ with $f(p_0) = 0$, $f(p_1) = d(p_0,p_1)$ and ...

**1**

vote

**0**answers

24 views

### Visibility kernels of embedded graphs

Let $G$ be a connected graph embedded in the plane with all edges straight segments.
For $\alpha \in (0,\pi)$, define an $\alpha$-path as a path in $G$ with
all turns at vertices within ...

**7**

votes

**0**answers

56 views

### Is such a map null-homotopic?

Suppose I have (semi-infinite) chain complexes $$ \cdots \rightarrow A_i \rightarrow A_{i+1}\rightarrow \cdots$$ $$ \cdots \rightarrow B_i \rightarrow B_{i+1}\rightarrow \cdots$$
over an additive ...

**2**

votes

**0**answers

43 views

### Better Sobolev inequality holds in this case when assuming doubling and Poincare inequality?

Let $X$ be a Polish space and let $m$ be a locally finite Borel measure on $X$.
Let $\epsilon$ be a strongly local, regular Dirichlet form on $L^2(X,m)$ with Domain $V :=\{f\in ...

**1**

vote

**0**answers

75 views

### Can the Gaussian integers be covered by restricted recurrences?

Relaxation of the second question here.
Let $a(n)$ be recurrence of the form $a(n)=f(n,a(n-1)\ldots(a(n-k))$
with fixed initial terms.
(Observe that it might depend on $n$).
$f$ may contain ...

**3**

votes

**1**answer

113 views

### Fano varieties of cubic threefolds

Let $X$ be a smooth cubic threefold over $\mathbb{C}$. Let $F(X)$ denote the Fano variety of lines in $X$, which is a smooth surface of general type.
Is this class of surfaces distingushed ...

**-8**

votes

**0**answers

67 views

### The Riemann Zeta Function Works [on hold]

1 - Any counterexamples known for the Riemann Zeta Function?
2 - How to generalize the following?
Here we have the visualization of the Riemann Zeta Function 3D Plot and the plane. We can observe ...

**-2**

votes

**0**answers

24 views

### Can this specific Mixed-Integer Linear Program constraint be expressed? [on hold]

Thanks for your time.
I have a linear program and no idea how I could express a form of constraint and even if it's possible. Maybe someone here know a solution.
A company assembly and sells a ...

**1**

vote

**0**answers

142 views

### What would be the consequences of $\displaystyle{\lim\inf_{n\to\infty}p_{n+k}-p_{n}\sim k\log k}$?

The question is in the title: what would be the number theoretic consequences if we managed to establish the conjectured asymptotic equality $\displaystyle{\lim\inf_{n\to\infty}p_{n+k}-p_{n}\sim k\log ...

**4**

votes

**0**answers

177 views

### Does Nelson try to prove PA inconsistent directly?

Edward Nelson is known for his serious attempts to show that Peano axioms, and sometimes even weaker theories, are inconsistent. I wasn't able to find Nelson's papers anywhere, so I wanted to ask a ...

**3**

votes

**1**answer

175 views

### Question on effective Mordell conjecture

Suppose $F(x,y,z)$ is a homogeneous polynomial over $\mathbb{Q}$, where $C:F(x,y,z)=0$ is a curve of genus $g\geq 2$.
Question: Faltings proved that $C$ has finite many rational points. Suppose that ...

**4**

votes

**1**answer

72 views

### almost huge embeddings and stationary correctness

Suppose $\kappa$ is an almost huge cardinal. Using the characterization of Theorem 24.11 in Kanamori's book, one can show that if $j : V \to M$ is an embedding derived from an almost-huge tower of ...

**-2**

votes

**0**answers

61 views

### Centralizer of element in group PSL(2,F_p) [migrated]

Is it true, that $\forall g\in PSL(2,F_p)\setminus\{e\}$, $Z(g)$ is Abelian?
I think that this is true, but i can't find a simple proof.

**-2**

votes

**1**answer

23 views

### Convert constraint to do convex optimization or use Lagrange multiplier method [on hold]

$w_1, w_2, w_3 ... w_n$ are the weights I need to find
I have the following constraint:
$|w_1| + |w_2| + .. |w_n| <= 5$
That is the sum of the absolute values of the weights has to be less than ...

**4**

votes

**1**answer

70 views

### Estimate of the sum Taylor's coefficients

Let
$f(x) = \begin{cases}\ln\frac{x}{e^x-1}, \quad x > 0; \\ 0, \quad\qquad x=0; \\ \ln\frac{-x}{e^x-1}, \quad x < 0. \end{cases}$
Power series in 0:
$f(x) = \sum_{n=1}^{\infty} a_n x^n = ...

**-1**

votes

**0**answers

42 views

### Lower bound for sum of binomial coefficients without summation [on hold]

I am new here. So, I will be happy if can somebody help me to find an answer for this proof.
I want to prove this lower bound:
$$
\log {{n \choose n_1}} \leq nlog {n} - n_1log(n_1) - ...

**2**

votes

**1**answer

82 views

### Curvatures preserved under the Kahler-Ricci flow

Maybe it is a trivial question. Is there any obvious reason that non-negative holomorphic bisectional curvature is preserved by (normalized) Kahler-Ricci flow, but non-negative Ricci curvature is not ...

**3**

votes

**0**answers

56 views

### Some questions on analytic vectors and the integrability of Lie-algebra representations

I would like to ask a number of questions about the theory of analytic vectors and the integrability of Lie-algebra representations, but before I do so, let me fix the terminology to be used in this ...

**9**

votes

**1**answer

154 views

### Is there an $L$ like inner model for $\sf Z$?

Godel proved the consistency of the axiom of choice with the axioms of $\sf ZF$ by showing that given any model of $\sf ZF$, there is a definable class which satisfies $\sf ZFC$.
The proof uses a lot ...

**11**

votes

**1**answer

207 views

### Who first noticed that Stirling numbers of the second kind count partitions?

When the Stirling numbers of the second kind were introduced by James Stirling in 1730, it was not combinatorially; rather, the numbers ${n \brace k}$ were defined via the polynomial identity
$$
x^n = ...

**1**

vote

**0**answers

47 views

### The number of blocks in Szemerédi Regularity Lemma

In mathematics, the Szemerédi regularity lemma states that every large enough graph can be divided into subsets of about the same size so that the edges between different subsets behave almost ...

**2**

votes

**1**answer

78 views

### Resolving nodes of a quintic CY 3-fold

Let's consider the following quintic 3-fold $X$:
\begin{equation}
\{(x_i) \in \mathbb{P}^4 \ | \ x_1f(x)-x_2g(x)=0\}
\end{equation}
for generic homogeneous polynomials $f(x),g(x)$ of degree four. It ...

**0**

votes

**0**answers

68 views

### Understanding Prof. Keevash's proof on the “Existence of Designs” [on hold]

I have tried to read Prof. Kevvash's paper on the "Existence of designs". I am finding it very tough to read it linearly. I am comfortable with the nibble ideas and probabilistic methods in general.
...

**3**

votes

**1**answer

77 views

### the eigenvalues of a generalized circulant matrix

A $2k\times 2k$ circulant matrix $\ C$ takes the form
\begin{align}
C= \begin{bmatrix} c_0 & c_{2k-1} & \dots & c_{2} & c_{1} \\
c_{1} & c_0 & c_{2k-1} & & c_{2} ...

**2**

votes

**0**answers

35 views

### Behavior of elementary symmetric polynomials near zero sets

It is straightforward to show (see Characterizing intersection of zero sets of elementary symmetric polynomials on R^n) that the set of points $\Lambda_{k}$ in $x \in \mathbb{R}^{n}$ with ...

**-4**

votes

**0**answers

32 views

### Compare time it takes to travel a curve and a line [on hold]

First posted in Math Stack Exchange:
http://math.stackexchange.com/questions/989690/compare-time-it-takes-to-travel-a-curve-and-a-line?noredirect=1#comment2025799_989690
Suppose you have a right ...

**5**

votes

**1**answer

201 views

### Polynomial recurrence relation covering the integers (and then Gaussian integers)

Say that a polynomial recurrence relation (my terminology)
for $f_i$ is:
$k$ initial conditions setting $f_1,\ldots,f_k$ to integers ($\in \mathbb{Z})$.
A recurrence equation of the form $f_i =$ a ...

**3**

votes

**0**answers

58 views

### Number of orbits of $\mathrm{SL}_2(\mathcal O_A)$ on $\mathbf P^1(A)$ when $A$ is a quaternion algebra

This is a reference request.
Let $A$ be an anisotropic quaternion algebra over $\mathbf Q$. Let $\mathcal O_A$ be a maximal order in $A$. Then $\mathrm{SL}_2(A)$ acts transitively on the right on ...

**0**

votes

**0**answers

37 views

### What is the state of art MIQP solver

I used Gurobi with a MIQP with 26 binary variables and 26*4 interaction term without any other constraint. The speed is very slow already.... I want to ask what is the state of art of MIQP solvers. ...

**0**

votes

**0**answers

39 views

### Intersection points of closed curves inscribed in a convex polygon

Suppose that I have two distinct simple closed curves, $C_1$ & $C_2$, and each is inscribed in a convex polygon, D. By inscribed, I mean tangent to each side of D. In particular, I am most ...

**-2**

votes

**0**answers

83 views

### Arranging books into bags [on hold]

I'm trying to find an algorithm to answer the following question (informal): given a (finite) set of distinct books of different (positive integer) sizes and a (finite) set of bags of different ...

**-4**

votes

**0**answers

50 views

### In Dedekind' construction of real numbers, what's wrong with this understanding [on hold]

in this prove, every cut corresponds to a real number. and a cut is a subset of Q.and cut have these three properties.1.is not empty 2.if p belong to this cut,any qp
so in my understanding, every cut ...