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bio website robertfilter.net
location Jena, Germany
age 32
visits member for 4 years, 1 month
seen Nov 18 at 19:56

If you like electrodynamic problems with solutions and their connections to current research, please visit www.problemsinelectrodynamics.com


Jan
19
comment Fourier Transform of an unsteady function
@loenbloy: Thank you for your fast response. I think the three given ones make a pretty decent picture of the situation, all from a slightly different perspective :) Greets
Jan
19
accepted Fourier Transform of an unsteady function
Jan
19
comment Fourier Transform of an unsteady function
Thank you for this answer and the additional information. I think there was a brain overflow in understanding where the $\delta$ comes from :) Greets
Jan
19
comment Fourier Transform of an unsteady function
Thank you again for the clarification! I now know that there is a difference in these two approaches :) Greets
Jan
19
comment Fourier Transform of an unsteady function
Thank you for your answer. I must admit that I never had any course on measure theory so I have to speculate that I really want to calculate the first version. Greets
Jan
19
asked Fourier Transform of an unsteady function
Jan
19
answered Simple Harmonic Oscillator Solution
Jan
19
comment Mathematical difference between white and black notes in a piano
Please, Rudi, it should be Helmhol t z. :)
Jan
18
comment Effect of curvature of spacetime on intrinsic geometric properties (under general relativity)
@Steven: Thank you for your further thoughts. First of all I have to state that the choice of a timeslice would be the gauge I was referring to - hence angles will depend on this choice. Second of all the author is referring to lines of sight - I would interprete these as light geodesics. So, to maybe find a compromise here: One could define such angles more generally but they would depend on the gauge. Is this along your lines of thought? Greets
Jan
18
awarded  Revival
Jan
18
comment Effect of curvature of spacetime on intrinsic geometric properties (under general relativity)
@Steven: Thank you for your thoughts - I am not sure if I get them correctly, though. Assuming you are in a dynamic spacetime you can go from A to B to C on some geodesic. How do you go to A from C? It wont be possible with respect to causality. So you will have to define an equivalence class of points A - but in a dynamical spacetime this construction will be due to a certain gauge - your angle will depend on this as well. I wanted to leave out these things for simplicity. Greets
Jan
18
comment Writing an Integral in Different Form?
@Willie Wong: Thanks you, I wrote small $n$'s if I remember correctly. Greets
Jan
18
comment Effect of curvature of spacetime on intrinsic geometric properties (under general relativity)
@Ronaldo: Now looking at the comments I think I have just done what you had in mind :) Greets
Jan
18
answered Writing an Integral in Different Form?
Jan
18
answered Effect of curvature of spacetime on intrinsic geometric properties (under general relativity)
Jan
14
comment Eigenfunctions of the Helmholtz equation in Toroidal geometry
@Hans Lundmark: Thank you for the hint. I just found the book in our library and will have a look. Is this a classic like the Courant-Hilbert?
Jan
14
comment Eigenfunctions of the Helmholtz equation in Toroidal geometry
@Willie Wong: Thank you for the correction. Indeed, I mean it in this way. It seems to as if it is just a historic issue of applied mathematics that some "special" functions (trigonometric, Bessel etc) paved their way into standard textbooks. Nevertheless, do you know if there are implicit definitions of solutions available like the elliptic ones? If I remember correctly, the Greens function of the Helmholtz equation is normally constructed from eigenfunctions of the Laplace... Isn't an application of this procedure applicable here somehow?
Jan
14
revised Eigenfunctions of the Helmholtz equation in Toroidal geometry
added 353 characters in body
Jan
14
comment Eigenfunctions of the Helmholtz equation in Toroidal geometry
@Hans: Thanks for pointing out to the error, I will correct it. And also thank you for the link. It really is a pitty that there is no reference given. Greets
Jan
14
asked Eigenfunctions of the Helmholtz equation in Toroidal geometry