Recent content by bndnchrs

Much appreciated. I believe this solves my question. Don't worry about revealing the "proof", I would say that this problem is just a redefinition of a small mechanism in a larger problem, which has nothing to do with linear algebra, actually, so letting me in on the mechanism is of no great...

I suppose it was late, and this meant I had to improperly state the question! Really, the question is does the set of RD vectors have nonzero measure over R^k, not whether they are dense or not. Of course the rationals are rationally dependent and dense, but they are a set of measure zero in R...

Hi guys: I've got a problem I've been working on for some weeks and this might be the key to unlocking it. The question is: Given a vector in R^k, what is the measure of the set of vectors whose components are rationally dependent? Rationally dependent means for a given vector, you may...

Hey, I'm doing some examples in QFT and I don't want to go too far with this one: Doing gauge symmetries, we first introduce the Unitary spacetime-dependent gauge transformation that gives us a gauge potential. With the new gauge added Lagrangian, I want to take its variation to confirm the...

right, just approximating x by floors and ceilings

Right: I just meant the ratio, not the relative error. I just did \frac{yours}{actual}I don't understand that third statement: the largest error in [m,n] is at m + sqrt(m)? This isn't always in the interval. I'm also not sure what you mean by 2) your largest error is at two points? The error is...

I think the easiest way to explain it is by what Wikipedia has: A Killing field is one where when you move points along the field, distances are preserved. So http://en.wikipedia.org/wiki/Killing_vector_field" when you'e got a Killing field.

This is like a weight combo of up and down Bahkshali, right?Here's your relative error: It has an exponential approach curve I think its a smart idea but computationally its as efficient as Bahkshali... and there are more efficient methods than Bahkshali. Mathematica isn't cooperating with...

Hi notist, If you are able to write down the perturbed Hamiltonian, you should be able to run through these computations quite easily :). The idea is that to first order perturbation, the energy shifts are essentially the same as the expectation value of the perturbing Hamiltonian. It...

should be moved to homework... sorry!

So here's the problem: I'm asked to find the solutions to the 1-D Wave equation u_{tt} = u_{xx} subject to u(x,0) = g(x), u_t(x,0) = h(x) but also u_t(0,t) = A*u_x(0,t) and discuss why A = -1 does not allow valid solutions. I can't figure it out at all. The solutions to...

right... the problem is this solution isn't as easy as all that... there is a more trivial example solved with \frac{dx}{x^2} = \frac{dy}{y^2} = \frac{dz}{z(x+y)} Which can be solved by doing some proper addition and subtraction: so I know the idea. Its a matter of getting a form \frac{g*dx...

Hey guys, I'm having a little difficulty with a pde I'm trying to solve. It boils down to solving for a first integral. I don't want the answer, but I'd be glad to get a little help. We have the system: \frac{dx}{x^2} = \frac{dy}{y^2} = \frac{dz}{xy(z^2 + 1)} We can use the first two and find...

Wheeler! Thanks!

Its a quote I want to use it on a proof, I just don't want to screw it up and attribute it to Feynman (though its a good chance its his). I also don't remember the precise wording. It goes something like this Thanks guys! I know one of you knows this, its pretty damn famous, about every...