All Questions
3
votes
0answers
21 views
Gelfand triple (H^(1+s), H^1, H^(1-s))
I think I found a proof, that on Lipschitz domains $\Omega$, $H^{1+s}(\Omega)$ is the dual space of $H^{1-s}(\Omega)$ with respect to the $H^1(\Omega)$ scalar product for all $0\leq s<1/2$. Does ...
0
votes
0answers
53 views
Affine spaces with non-torsion homotopy groups
Is there some kind of classification of affine spaces such that every homotopy group of the space has no torsion? Any reference on this topic will be most welcome.
0
votes
1answer
58 views
Understanding Polish notation in Lukasiewicz's axioms
In a paper about Presburger Arithmetic, Lukasiewicz's axioms of propositional calculus are written as follows:
CCpqCCqrCpr
CCNppp
CpCNpq
I am having a hard time understanding what these axioms ...
0
votes
0answers
16 views
Interesting examples of weakly nonlocal elliptic PDEs
A weakly nonlocal second order elliptic PDE is one which can be expressed in the form
$$F(x,u,Du(x),D^2u(x))=0$$
where $F(\cdot,\cdot,\cdot,X) \leq F(\cdot,\cdot,\cdot,Y)$ whenever $Y \preceq X$.
...
2
votes
0answers
29 views
Variation of the Green function with respect to the metric
Consider a (closed) Riemann surface and let $G(x,y)$ be the Green function of the Laplace-Beltrami operator. We can informally identify $G$ with the two-point correlation function for the Gaussian ...
1
vote
0answers
44 views
A consequence of the complete reducibility theorem
In a paper by Roitman there is the following argument in the proof of the Proposition 3.4:
Let $f:A\to B$ an epimorphism of abelian varieties. By the complete reducibility theorem (see Mumford´s ...
9
votes
1answer
155 views
Torsion in the Atiyah–Hirzebruch spectral sequence of a classifying space
Let $G$ be a compact, connected Lie group. There is an Atiyah–Hirzebruch spectral sequence
$$H^*(BG;K^*) \implies K^*(BG)$$
connecting $H^*BG$, which generally contains torsion, with $K^*BG \cong \...
3
votes
0answers
90 views
Dijkgraaf-Witten topological invariant
We know that given a finite group $G$ and its group 4-cohomology class $w \in H^4[G;U(1)]$, we can obtain a DW topological invariant $Z_{G,w}(M^4)$ as the partition function of the DW theory on a ...
-5
votes
0answers
26 views
Advanced engineering maths,a masters student [on hold]
Please I find it quite different to evaluate the terms Ao and Bo from these expressions and before then I need to evaluate P2m and Q2m.how do I figure out these four quantities on the screen shots ...
1
vote
0answers
50 views
Quantization in semiclassical analysis
I have a question about some notation in the book "Semiclassical Analysis":
What worries me is the interpretation of the derivative $D_{x_j}$ in the third and second-to last equation.
The author ...
0
votes
0answers
18 views
Characterization of polyconvex function with eigenvalues/eigenvectors
Consider a function $f:\mathbb{R}^{2\times 2} \rightarrow \mathbb{R}^{2\times 2}$.
$f$ convex is characterised by the sign of the eigenvalues of the Hessian matrix of $f$.
Is there a similar ...
1
vote
0answers
24 views
Meromorphic continuation of resolvent of free Laplacian on homogeneous Sobolev space
Let $n \ge 2$. Set $\dot{H}^1(\mathbb{R}^n)$ to be the homogeneous Sobolev space, defined as the Hilbert completion of $C_0^\infty(\mathbb{R}^n)$ with respect to the norm $\| \varphi \|^2_{\dot{H}^1} \...
4
votes
1answer
36 views
Asymptotic behavior of the ratio between the largest two singular values of product of i.i.d. random complex matrices
Let $A_n$ be the matrix product of $n$ i.i.d. N-by-N random complex matrices. The matrix distribution is not fixed and can be tuned to suit specific solution if needed, as long as it's not too "...
0
votes
0answers
40 views
Homeomorphism Question [migrated]
Is there any homeomorhpism from $\mathbb R^n$ to $\mathbb R^n$ that transforms an ellipsoid of the form $\{x|x^T A x\leq 1\}$ (=ellipsoid centered at the origin) into a hyperrectangle, and transforms ...
3
votes
2answers
70 views
Energy methods for first order systems
I have trouble to find references on the use of energy method (Faedo-Galerkin method using approximation in finite dimension space) to solve problems of the form
$$ \begin{cases} \partial_t u = \...