bio | website | math.tsukuba.ac.jp/~carnahan |
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location | 筑波市, Japan | |
age | ||
visits | member for | 5 years, 2 months |
seen | 4 hours ago | |
stats | profile views | 16,808 |
I think this is a neat project.
Dec 14 |
comment |
Why do sporadic simple groups have so few conjugacy classes?
An equivalent question is, why do sporadic simple groups lack small representations? |
Dec 12 |
answered | A kind of Discrete Fourier Transform |
Dec 12 |
reviewed | Leave Open Dihedral subgroups of $\mathrm{PSL}_2(\mathbb{F}_q)$ |
Dec 12 |
reviewed | Close Clarification about Joyal's notation |
Dec 12 |
comment |
What is the etale fundamental group of Spec Z((x))?
There is a non-trivial automorphism of $\mathbb{Z}((x^{1/2}))$. |
Dec 12 |
revised |
Number of singular fibers in families of hypersurfaces
edited tags |
Dec 11 |
comment |
Decomposing quasi-finite separated group schemes
The last question has a negative answer, because you don't have any hypotheses that distinguish $0$ from any other point in the disk. You may want to specify that the pullback of $G$ to the punctured disk is étale, or something. |
Dec 11 |
comment |
A kind of Discrete Fourier Transform
Your general DFT is just the restriction of an $N$-tuple of DFTs along the diagonal. That is, you really have a more general DFT: $$MGDFT_z(\ell,k)=\frac{1}{N}\sum_{j=0}^{N-1}z_{\ell,j} \omega^{-kj}$$ which is invertible, but you are forgetting most of the information by setting $k=\ell$. MGDFTs appear in many places, since they are just vector-valued DFTs. I have never seen an application of the GDFT by itself - you can certainly prove elementary properties like norm bounds by passing to the MGDFT, but if you don't tell us what sort of specific results you seek it is difficult to say more. |
Dec 11 |
comment |
Most dispersed set of points in a disk?
@GerryMyerson You might as well turn your comment into an answer, since we are unlikely to see anything better in the near future. |
Dec 10 |
comment |
Link between Virasoro algebra and Heisenberg algebra
See also mathoverflow.net/questions/16392/… |
Dec 9 |
awarded | Enlightened |
Dec 9 |
awarded | Nice Answer |
Dec 3 |
reviewed | Close totally disconnected sets and homeomorphisms |
Dec 3 |
reviewed | Reopen Affine communication lemma and finite limits in the category of rings |
Dec 3 |
comment |
Relationship between Verma modules and delta functions
This seems to be a restatement of a theorem of Beilinson and Bernstein that gives an equivalence of categories between monodromic $D$-modules on the flag variety and representations of $G$. You can write generating elements of the $D$-modules as distributions corresponding to highest-weight vectors. |
Dec 2 |
comment |
Can these two proofs of the parametrization of pythagorean triples be unified?
The second proof also appears on this site: mathoverflow.net/a/10903/121 |
Dec 1 |
reviewed | Close How can we join two points with a small ruler? |
Dec 1 |
comment |
The resolution of which conjecture/problem would advance Mathematics the most?
@JosephO'Rourke I don't think the list order is indicative of anything. After all, P vs NP is "número tres" at claymath.org/millennium-problems . |
Nov 30 |
comment |
Affine communication lemma and finite limits in the category of rings
My best guess at your intention is that you want to prove that certain properties of affine schemes are Zariski-local in nature, and you are asking how to eliminate certain repetitive aspects of the standard arguments. Is that correct? |
Nov 29 |
reviewed | Close Affine communication lemma and finite limits in the category of rings |