7,002 reputation
22248
bio website people.ucsc.edu/~weissman
location Around and about
age 38
visits member for 4 years, 10 months
seen 5 hours ago

Associate Professor, Yale-NUS College, Singapore.

Associate Professor of Mathematics, UC Santa Cruz. (On leave)

Research interests: Automorphic representations and representations of p-adic groups, especially exceptional groups and "metaplectic" groups lately. Theta correspondences (exceptional ones). Geometric methods in representation theory. Periods and Hodge theory. Model theory applied to number theory and geometry.

Book blog: Illustrated Theory of Numbers


Nov
16
comment Weil index computation, p-adic integral
These computations should be straightforward, using the explicit formulas of Ranga Rao. See the appendix of "On some explicit formulas in the theory of the Weil representation" in Pacific J. of Math., Vol. 157, No. 2, 1993.
Nov
3
comment What are the higher homotopy groups of a K3 suface?
A new entry in the encyclopedia of integer sequences, perhaps?
Oct
28
comment Visibility interpretation of Riemann zeta zeros on the critical line?
You forgot to mention, the fraction of $\mathbb Z$ lattice points visible from the origin is $1 / \zeta(1) = 0$.
Oct
26
comment Does every smooth, projective morphism to $\mathbb{C}P^1$ admit a section?
@Jason: But I guess that by removing a bunch of codim 1 subvarieties from Y, we'd get something $U$ which is "anabelian" or "hyperbolic" in some sense of the word. Then a rational section (existing by anabelian section conjecture) from $P^1 C \rightarrow U$ would extend to a regular section $P^1 C \rightarrow Y$. Again, all contingent on some anabelian conjectures that I don't fully understand.
Oct
25
comment Does every smooth, projective morphism to $\mathbb{C}P^1$ admit a section?
Does this follow from some anabelian conjecture? From such a conjecture, we might expect rational sections $P^1 C \rightarrow Y$ to arise from sections of $Gal(Y) \rightarrow Gal(P^1 C)$ (abs. Galois group of function fields). It's known (Harbater, Pop, Haran, I think) that $Gal(P^1 C)$ is profinite free, and so sections exist. A rational section $P^1 C \rightarrow Y$ gives a regular section by the valuative criterion, right? Or perhaps a counterexample to this type of anabelian conjecture provides a counterexample here?
Sep
22
awarded  Enlightened
Sep
15
comment Results true in a dimension and false for higher dimensions
Every cubic polynomial map from $\mathbb C^n$ to $\mathbb C^n$ with nowhere vanishing Jacobian is a bijection. This is true for $n \leq 17$ but fails for larger $n$. Just kidding... but perhaps someday I'll edit the answer, change 17 appropriately and will gain some upvotes.
Sep
5
comment Recognize this strange expression from linear algebra?
Ahh - or arrgh.. This gets more interesting though. I'll think about how to phrase things in terms of a cocycle. And please don't take offense for the removal of acceptance. I'm also hoping that someone might recognize it from another context and contribute another answer.
Sep
3
comment Recognize this strange expression from linear algebra?
Wonderful, thank you! (And you did say "cocycle".)
Sep
2
comment Recognize this strange expression from linear algebra?
Nick - I can only take credit for the pasta-related one. But I'll keep the other to maximize the tag-contribution.
Sep
2
awarded  Nice Question
Sep
2
asked Recognize this strange expression from linear algebra?
Aug
29
answered Are the quaternions not uncountably categorical?
Aug
16
awarded  Enlightened
Aug
13
comment What is the analogue of simple prime closed geodesic for prime numbers?
Birman and Series (J. Lond Math Soc 1984) characterize non-self-intersection of a closed loop via a group-theoretic property of the corresponding element in the fundamental group. Their characterization depends on the Nielesen generators available for $\pi_1$ of cpt orientable surfaces with non-empty bdry. Wild out of the blue idea: try something similar, with Frobenius at $p$, and the usual generators of the Grothendieck-Teichmuller group.
Aug
8
comment Examples of research on how people perceive mathematical objects
Have you seen George Lakoff, "Where mathematics comes from?" He's a cognitive linguist at Berkeley, well-known for work on metaphor. See amazon.com/Where-Mathematics-Come-From-Embodied/dp/0465037712
Jul
2
awarded  Curious
Jun
26
awarded  Nice Answer
Jun
6
revised How to estimate the Haar measure on $G_2$
expressed my growing confidence :p
Jun
6
revised How to estimate the Haar measure on $G_2$
Changed a 6 to a 7.