7,861 reputation
2833
bio website supermath.info
location Virgina USA
age 36
visits member for 2 years, 3 months
seen 8 hours ago

I'm interested in mathematics which is used to frame physical theory. I guess that means I'm at least a little interested in just about anything.

Currently I'm trying to understand Cartan's Method of moving frames as it applies to various classification questions of low-dimensional geometry.

I also have interest in superanalysis and certain problems of hypercomplex analysis.

More generally, I'm just looking for interested students who want to exceed the status-quo of undergraduate mathematics. Ideally, our interests overlap.


Jun
21
comment Inexact Differential Equations: how to know if μ will be a function of x or y instead of guessing?
interesting answer, do you happen to have a link to the paper of Lie you mention? Also, how do you identify the "family of groups" for the given ODE?
Jun
20
comment When is separation of variables possible?
this question is far deeper than it appears. See ima.umn.edu/~miller/sepofvariablestalk.pdf for a sense of why this question must be narrowed to obtain a good answer. I think if you limit it to Hamilton-Jacobi in a reasonable context the linked items shows you what's what.
Jun
20
reviewed Approve suggested edit on Orientation double cover
Jun
20
comment A confusing vector field differential
@Bye_World yes, this in my conclusion as well, in the absence of additional data or context the identity is false.
Jun
20
comment Is $ 5 $ nearer to $ 0 $ or $ 10 $?
this answer currently violates the answers with pictures get lots of votes principle. curious.
Jun
19
comment Abuse of notation in declaring a variable is a function of another?
Excellent take on this issue. +1
Jun
18
comment A confusing vector field differential
@SchlomoSteinbergerstein in my current notation $e_1 = \langle 1,0,0 \rangle$.
Jun
18
comment Why is an orthogonal matrix called orthogonal?
@rschwieb it could be worse, at least we only have two components to worry about here :)
Jun
18
comment Why is an orthogonal matrix called orthogonal?
@rschwieb that may be, let me check... well, not in O'neill's Elementary Differential Geometry (which I happen to have sitting here) on page 100 he indicates rigid motion as just another name for isometry. I suppose, the question is, is a reflection a rigid motion?
Jun
18
comment Why is an orthogonal matrix called orthogonal?
@littlO I expanded your comment.
Jun
18
answered Why is an orthogonal matrix called orthogonal?
Jun
18
comment Why is an orthogonal matrix called orthogonal?
A matrix of nonzero orthogonal columns is of some interest. Notice this condition is sufficient for invertibility. Not as awesome as $A^{-1}=A^T$, but, still noteworthy.
Jun
18
comment What's a “right” approach of studying complex analysis?
you might look at Remmert's text Theory of Complex Functions. You've already had some exposure, this text goes far deeper and yet is readable.
Jun
18
revised A confusing vector field differential
added 567 characters in body
Jun
17
answered A confusing vector field differential
Jun
17
comment Complex integral inequality
$\sin (x+iy) = \frac{1}{2i}(e^{x+iy}-e^{-x-iy})$
Jun
17
comment Reference Request: How to Parametrize Curves and Surfaces in $\Bbb R^3$
you will probably find Chapter 12 of supermath.info/OldschoolCalculusII.pdf useful to your study. I make an effort to discuss the three major view points as well as common parametrizations.
Jun
17
answered Reference Request: How to Parametrize Curves and Surfaces in $\Bbb R^3$
Jun
17
comment What's the advantage of defining topologies on open sets rather than closed sets?
keep an open mind, wait, maybe closed?
Jun
16
comment Differential Equations and Eigenvalues
Also, multiplying by 2 would also multiply the $dy/dt$. More to the point, the trace of the original matrix is $-2$ and the determinant is $-3$ which matches the sum and product of your given e-value answer. A good thing.