Wolfram Mathematica

Problem with Get'ting files with << as opposed to Get

When trying to import some files into my Mathematica notebook, I wanted to use ToString to specify the file path. Consider the following MWE, where we export some expression to the directory of the notebook, and immediately import it back: In:= Export]<>"output.txt", 2020]; import1 = Import]<>"output.txt"] Out= "2020" This works ....

Micah Micah: 3 hours ago

Physics

What opposes a smooth motion of a rubber eraser on a glass surface?

A metal block smoothly moves on a glass surface. But a rubber eraser doesn't move very smoothly on a glass surface. In each of the cases, the surfaces are smooth at the macroscopic scale. If the latter is due to friction at the molecular level, how come a metal block ....

Matthew Matthew: 3 hours ago

Math

Seeking very regular $\mathbb Q$-acyclic complexes

This question was raised from a project with Nati Linial and Yuval Peled We are seeking a $3$-dimensional simplicial complex $K$ on $12$ vertices with the following properties a) $K$ has a complete $2$-dimensional skeleton (namely, every triple of vertices form a 2-face of $K$) and it has $165$ $3$-simplices. ....

Isabella Isabella: 3 hours ago

Math

Berry–Esseen bound for operator norm of matrix averages

Is there a Berry–Esseen bound for operator norm of an average of independent random matrices? Suppose $A_1, \dotsc, A_n$ are independent matrices with $\mathbb{E} = I$ (the identity matrix). Is there a Berry–Esseen bound for properly normalized $\lVert\overline{A} - I\rVert_\text{op}$? ....

Addison Addison: 3 hours ago

Academic

How familiar should I be with research topics of a potential PhD supervisor?

I'm about to finish my master's degree in physics (theoretical physics). I'm applying for several professors in Europe. I want to do my PhD in another field than my master's thesis, but both fields are theoretical and to some extend related. But, I didn't take some relevant courses on this ....

Layla Layla: 3 hours ago

Wolfram Mathematica

Update an application on the click of a Button

I am finishing my first program in Wolfram Mathematica 10 and if I have almost completed is essentially thanks to this valuable forum soon where I will try to help too. Basically, now I have this problem: to make work a routine I used Button]. Unfortunately, in this program you ....

Eli Eli: 3 hours ago

Computer Science

Definition of Lagrange nodes in Gmsh

When gmsh uses higher-order tetrahedral elements, there is an underlying Lagrange basis used to specify the map from reference space to the element. I'm trying to load a gmsh mesh of 3rd degree tetrahedral elements, but I can't seem to find any precise documentation on the location of the nodes ....

Charlotte Charlotte: 3 hours ago

Physics

Negative Magnus effect?

Supposedly, the Magnus effect, which is responsible for the curve of a curveball, and is the reason that tennis players hit their ground strokes with topspin, only acts above a critical Reynolds number ($\mathrm{Re}=Ud/\nu$, where $U$ is the velocity, $d$ is the diameter, and $\nu$ is the kinematic viscosity) of ....

Greyson Greyson: 3 hours ago

Physics

Do atoms behave like waves?

I've heard someone state that the double slit experiment can also be done with atoms, not just electrons or photons of light. ....

Aaron Aaron: 3 hours ago

Biology

Are there examples of animals being sexually attracted to another species more than to their own?

I just thought that from the perspective of a female domestic cat, a male bobcat probably looks like the archetype of a perfect mate. As tall, strong, muscular and mighty as it possibly gets. Clearly preferable to any of these boring male domestics. Has anyone ever done any research on ....

Thomas Thomas: 3 hours ago