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RaphaelB4's user avatar
RaphaelB4's user avatar
RaphaelB4
  • Member for 8 years, 2 months
  • Last seen more than 1 year ago
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Simple properties of the codifferential
I will be happy already with the simple euclidienne metric. And one can think V or W as $\mathbb{R}^n$, $\mathbb{S}^n$ or $\mathbb{T}^n$ if it does make the question simpler.
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What is the simplest proof that the density of primes goes to zero?
I guess this is the proof Kim talked about when he mention the binomial coefficients.
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Laplacian on manifolds and random matrix theory
If $g$ has a very strong disorder, I think one should not be too surprise to see Anderson localisation phenomenom there. (But this is a completely behaviour.)
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Example of ODE not equivalent to Euler-Lagrange equation
Isn't Euler Lagrange equation equivalent to Hamiltonian's and therefore implies conservation laws ? So I guess anything with a dissipative term, for example $\frac{d^2}{dt^2}q = -\frac{d}{dt}q$ should be a counter example.
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$\ell^1$-norm of eigenvectors of Erdős-Renyi Graphs
I apologize for self advertising. In our paper arxiv.org/abs/2005.14180 we deal with this problem for the adjancy matrix of the E-R graph.
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Find an element with given periodicity
$f(x_1,x_2)=e^{i\pi x_1x_2}$ ?
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Does a subset of positive measure in $\mathbb{R}$ locally "almost" have density $1$?
Don't you mean : "Clearly if $A$ is locally $\epsilon-$dense then $A$ has positive measure"?
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$M = AA^t$ where $A$ has unit norm columns
And you can have both: a permutation matrix with $\pm 1$ entries.
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Every mathematician has only a few tricks
@ogogmad For physicists all matrices are diagonalizable except for the matrices than are not.
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$M = AA^t$ where $A$ has unit norm columns
What about $D$ a permurtation matrix?
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If $(Y_n)_{n\in\mathbb N_0}$ and $(N_t)_{t\ge0}$ are stochastic processes, what is the filtration generated by $\left(Y_{N_t}\right)_{t\ge0}$?
One condition I guess should be that $Y_m\neq Y_{m+1}$ a.s. otherwise there is no way one can see the time when $N_{t}=m+1$ occures.
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