Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options questions only not deleted user 103792

Partial differential equations (PDEs): Existence and uniqueness, regularity, boundary conditions, linear and non-linear operators, stability, soliton theory, integrable PDEs, conservation laws, qualitative dynamics.

9 votes
1 answer
586 views

When does the eikonal equation $\lvert Du \rvert^2 = f$ admit a local solution?

Let $f$ be a smooth function defined on the unit disc $D \subset \mathbf{R}^2$ with \begin{equation} f \geq 0 \text{ in $D$ and } f(0) = 0. \end{equation} This is allowed to have a degenerate minimum …
Leo Moos's user avatar
  • 5,048
6 votes
0 answers
118 views

Entire solutions of the Ginzburg-Landau equation in the plane

Question. Are all solutions $u: \mathbf{R}^2 \to \mathbf{C}$ of the Ginzburg-Landau equation (1) radially symmetric? What if one imposes additionally that $\int_{\mathbf{R}^2} ( 1 - \lvert u \rvert^2) …
Leo Moos's user avatar
  • 5,048
6 votes
0 answers
318 views

Are the two-valued homogeneous harmonic functions classified?

Question. Is there a classification of homogeneous two-valued harmonic functions on $\mathbf{R}^n$, valid in dimensions $n \geq 3$? For reference, multi-valued functions are familiar objects in comple …
Leo Moos's user avatar
  • 5,048
5 votes
0 answers
165 views

Singularities of phase interfaces in closed surfaces

Let $(\Sigma,g)$ be a compact surface without boundary. Given $\epsilon > 0$, the $\epsilon$-Allen-Cahn equation is the semilinear elliptic PDE $\epsilon \Delta_g u - \epsilon^{-1} W'(u) = 0$, with un …
Leo Moos's user avatar
  • 5,048
4 votes
0 answers
148 views

What role do semiclassical methods play in the study of Ginzburg--Landau-type equations?

As far as I understand, semiclassical limits are used in quantum mechanics to analyse equations that depend on a small parameter $\hbar$. Apparently studying properties of the PDE as $\hbar \to 0$ sho …
Leo Moos's user avatar
  • 5,048
4 votes
1 answer
336 views

Is there a harmonic function with just one singular point?

Let $D \subset \mathbf{R}^2$ be the unit disc, and $L > 0$. Let $u: D \times (-L,L) \to \mathbf{R}$ satisfy \begin{equation} \begin{cases} \Delta u = 0 \quad \text{ on $D \times (-L,L)$ } \\ \frac{\p …
Leo Moos's user avatar
  • 5,048
3 votes
1 answer
343 views

Does the difference of solutions of two unrelated PDE solve an 'intermediate' equation?

I should preface this question by saying that I strongly suspect the answer is negative, but I couldn't find the counterexample myself. Say we are working on the unit disc $D \subset \mathbf{R}^n$, wh …
Leo Moos's user avatar
  • 5,048
3 votes
1 answer
107 views

A harmonic function degenerate in one direction

Question. Let $u: B^3 \to \mathbf{R}$ be a harmonic function with $u(0) = 0$, $Du(0) = 0$, where its homogeneous harmonic blow-up is a polynomial $p = p(x,y)$ in two variables, so independent of $z$; …
Leo Moos's user avatar
  • 5,048
3 votes
0 answers
116 views

Approximation of viscosity subsolution

Let $u: \Omega \to \mathbf{R}$ be a $C^{0,\alpha}$ function, with $\alpha \in (0,1]$, defined on a bounded, open domain $\Omega$. Suppose that $u$ is a viscosity subsolution of the equation $\Delta U …
Leo Moos's user avatar
  • 5,048
3 votes
0 answers
56 views

Intersection of $n$-dimensional minimal surfaces with two-dimensional planes

Let $M^n \subset \mathbf{R}^{n+k}$ be a smoothly embedded minimal surface. When the dimension is $n = 2$ and the codimension is $k = 1$ the intersection of $M$ with planes is well understood. If $M$ a …
Leo Moos's user avatar
  • 5,048
3 votes
1 answer
145 views

'Degenerate' tangent point of a minimal graph

Let $u: D_1 \to \mathbf{R}$ be a smooth function defined on the unit disk $D_1 \subset \mathbf{R}^2$ which describes the minimal graph $G$. Suppose that at the origin $G$ is tangent to the horizontal …
Leo Moos's user avatar
  • 5,048
3 votes
2 answers
381 views

Heating a long cylinder: steady states

Consider a long cylinder $C = D \times (-L,L) \subset \mathbf{R}^3$, with heat applied to its horizontal boundary according to $\varphi$ and perfectly insulated ends. The steady state $u: C \to \mathb …
Leo Moos's user avatar
  • 5,048
2 votes
0 answers
148 views

Extensions of minimal hypersurfaces

Let $B \subset \mathbf{R}^{n+1}$ be the unit ball, and $M \subset B$ be a minimal hypersurface. By this we mean that $M$ is an embedded $n$-dimensional submanifold with vanishing mean curvature. We al …
Leo Moos's user avatar
  • 5,048
2 votes
0 answers
207 views

Can you compute one eigenspace without computing them all?

Maybe the simplest non-trivial settings in which the spectrum of the Laplacian be can be computed is on the round sphere $\mathbf{S}^n$, and for products of manifolds. I want to use the two as example …
Leo Moos's user avatar
  • 5,048
2 votes
1 answer
184 views

Reference for harmonic functions in cylinders

Question. What is a good reference (textbook, article etc.) to learn more about harmonic functions on finite (and infinite) cylinders? I am trying to gain a better understanding of the behavior of har …
Leo Moos's user avatar
  • 5,048

15 30 50 per page