Dec
2
comment classical solutions of PDE with mixed boundary conditions
Thanks. These and especially their reference to Azzam and Kreyszig are very useful!
Nov
13
comment Eigenvalues of a bipartite graph
@Shahab: It implies that $k|x|=A|x|$. For if this fails then there is strict inequality in at least one component, and multiplication by $u^T>0$ gives a strict inequality, contradiction.
Nov
9
comment Spectrum of a Block Matrix
@Timothy: intuitively: Draw a graph of the corresponding quadratic functions and you'll see where the inequalities hold. - formally: complete the squares, take square roots, and discard the signs not compatible with the case.
Nov
7
comment Spectrum of a Block Matrix
What is your motivation for this conjecture?
Nov
6
comment Number of local maxima of a function
@EwanDelanoy: $F(x)=c$ is the quotient of two polynomials of degree $2k$. So my original $2k-1$ was one off. I corrected the mistake.
Jul
28
comment recovering a representation from its character
@JackSchmidt: Thanks. At the moment, this is more than enough for the finite case.
Jul
28
comment recovering a representation from its character
@JackSchmidt: I am actually not interested in a computer program but in the conceptual ideas behind such an algorithm. So a reference to the original papers would be a useful answer.
Jul
24
comment Weyl's unitarity trick
@QiaochuYuan: At Wikipedia, there is an explicit reference to a paper by Hurwitz but none to Weyl, though his name is mentioned.
Jul
21
comment Intertwiner in german?
google books says that it is not avialable to me for viewing. Could you please give the page number?
Jul
18
comment Intertwiner in german?
It is not enough to find possible translations; since the concept is old one also needs references for actual usage in this context. (Verschlingung sounds more like braiding, which has a very different meaning in group theory.)
Jul
18
comment Intertwiner in german?
@AsafKaragila: Milne forgot to add explanatory notes to the 11th tip. German is not a bad languague for expressing mathematics.
Jul
18
comment Intertwiner in german?
I had done just that before posting the question, but I would have liked to have a single word translation rather than 9 syllables. - Would the term ''äquivariante Abbildung'' also be appropriate for intertwiners between representations of an algebra?
Jul
6
comment Infinite-dimensional translation-invariant measure
I am interested in an infinite-dimensional space with a definite inner product but not necessarily closed in the corresponding topology. Thus it need not be a Hilbert space.
May
24
comment classical solutions of PDE with mixed boundary conditions
Thanks. I hadn't realize before that the pure Neumann case is in Gilbarg/Trudinger which I generally know quite well. I still hope to get info on the mixed case from somewhere....
Mar
22
comment Special solution of Helmholtz equation
Thanks. This construction is good enough for me.
Mar
21
comment Special solution of Helmholtz equation
But doesn't the differential equation have to hold only in the interior? Wouldn't your statment just mean that the second derivative cannot be continous at the corners?