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Elliptic, parabolic and hyperbolic operators. Laplace, Laplace-Beltrami, Schrödinger, Dirac. Exterior derivative and Lie derivative operators.

1 vote
0 answers
187 views

Spektrum of special Laplace type operator

How can I find Eigenvalues of the differential operator $-\frac{d^2}{dt^2} + \mathrm{sin} =\Delta + \mathrm{sin}$, defined on $M=S^1$, the 1-Sphere? It seems that the underlying ODE is pretty much un …
Matthias Ludewig's user avatar
5 votes
1 answer
614 views

Symbol map in Getzler calculus

I hope someone can help me, although this question is rather specific. I am reading John Roe's chapter on Getzler symbols in "Elliptic operators, topology and asymptotic methods" to understand the pr …
Matthias Ludewig's user avatar
1 vote
1 answer
316 views

Combinatorics: Product Rules.

I couldn't find a way to figure this out, though it is a somewhat basic question that came up when studying the stationary phase expansion of an integral. The abstract version is the following: I hav …
Matthias Ludewig's user avatar
3 votes

de Rahm Laplace operator on forms bounded

Differential operators are never bounded unless they are of order zero. Standard references are Berline, Getzler, Vergne, "Heat Kernels and Dirac Operators" and Gilkey, "Invariance Theory, The Heat E …
Matthias Ludewig's user avatar
1 vote

Conjugacy of $L_X$ operators

For appropriate choices of $i$, $j$ (e.g. $i+j \neq n$), $\Omega^i(M)$ and $\Omega^j(M)$ have different ranks as $C^\infty(M)$ module, so at least they cannot be isomorphic as modules. Maybe they coul …
Matthias Ludewig's user avatar
2 votes
2 answers
320 views

Smooth dependence of the spectrum on the operator

I would like to know if there are theorems that state under which circumstances spectra of operator families depend smoothly on the parameter. To clarify, suppose I have a 1-parameter family $T_h$ of …
Matthias Ludewig's user avatar
4 votes
1 answer
679 views

Horizontal lift of differential operator

On a Riemannian manifold $M$, there is a canonical horizontal lift $X^{\mathrm{hor}}$ of vector fields $X$ to $TM$, which is characterized by the two properties that $X^{\mathrm{hor}}$ is a horizon …
Matthias Ludewig's user avatar
1 vote

Fredholm index vs. Limit cycle theory

The linearization of the vector field $X$ at the singular point zero is $$DX|_0 = \begin{pmatrix} 1 & 1\\ -1 & 0\end{pmatrix},$$ the eigenvalues of which are $$ \lambda_{1, 2} = \frac{1}{2} \pm \frac{ …
Matthias Ludewig's user avatar
1 vote
1 answer
271 views

Laplacian on space of measures

Let $X$ be a compact Riemannian manifold and let $\mathcal{M}(X)$ be the space of regular finite Borel measures with the total variation as norm. The Laplace-Belrami-Operator $\Delta$ on $X$ with do …
Matthias Ludewig's user avatar
1 vote
1 answer
393 views

Pullback via flow as operator group

Let $X$ be a vector field on a manifold $M$ that induces a complete flow $\Theta_t$. Then the operator family $\Theta_t^*$, $$\Theta_t^*u(x) = u(\Theta_t(x))$$ is a strongly continuous semigroup of op …
Matthias Ludewig's user avatar