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6 votes
0 answers
93 views

Computing all eta quotients of given weight and level

I have written a rather naive program for finding all holomorphic eta quotients of given weight and level (and varying character). When the level has few divisors it is very fast, but incredibly slow ...
Henri Cohen's user avatar
  • 13.1k
5 votes
0 answers
141 views

Compute weight of modular form from its Fourier coefficients

It is known that Hecke eigenform $f \in S_{k}(\Gamma_0(N), \chi)$ is uniquely determined by first $C_{k,N}$ many Fourier coefficients, where $C_{k,N}$ is a constant only depends on $k$ and $N$. For ...
Seewoo Lee's user avatar
  • 2,215
5 votes
1 answer
172 views

Isogenous elliptic curves and canonical modular polynomials

Let $\ell$ and $p$ be two primes. We are looking for a method for checking whether two supersingular elliptic curves over the finite field $F_p$, given through their $j$-invariants, are $\ell$-...
user447243's user avatar
5 votes
0 answers
195 views

Is there some computational evidence of the $pq$ analog of Serre's conjecture?

The $pq$ analog of Serre's conjecture (see "Mod pq Galois representations and Serre's Conjecture"- Khare, Kiming) states that if $\bar{\rho}_1:G_{\mathbb{Q}}\rightarrow \text{GL}_2(\mathbb{F}_p)$ is a ...
user avatar
5 votes
0 answers
228 views

Example of level one cuspidal Hecke Algebra T_k^0 such that p divides its index in its normalization, and p≥k-1?

The question is strongly focused on computations concerning modular forms and Hecke algebras. It is already in the title, but I will repeat it, adding a few details. Let $S_k$ be the complex vector ...
Tommaso Centeleghe's user avatar
4 votes
0 answers
143 views

Road map for learning about the computational/general theory of modular curves/isogenies of abelian varieties for cryptography

I am a graduate math/crypto student. So I've had some free time last year and I heard about elliptic curves in cryptography and how a resilient cryptosystem got demolished by a spectacular attack ...
Rayane B.'s user avatar
4 votes
0 answers
206 views

What are the modularity conjectures for Artin motives?

Classically, singular cohomology is an important tool for studying topological spaces, in particular, complex varieties. In the mid-twentieth century it was realized that there are many analogues of ...
David Schwein's user avatar
4 votes
0 answers
102 views

Reconstructing coefficients of an elliptic curve L-series from the modular form divisor

Let $E$ be an unknown elliptic curve over $\mathbb{Q}$. Let $L(E, s) = \sum_{n=1}^{\infty} \frac{a_n}{n^s}$ be the L-function of $E$ and write $f(q) = \sum_{n=1}^{\infty} a_n q^n$. I'm in a setting ...
Andreas Holmstrom's user avatar
3 votes
0 answers
203 views

Fourier expansions of newforms at width-1 cusps

Let $f_E$ be the newform attached to the Elliptic Curve $E$ with cremona label $\textbf{100a1}$ and let $\alpha = \left[\begin{matrix} 1&0 \\ 10&1 \end{matrix}\right] \in SL_2(\mathbb{Z})$. ...
Hao Chen's user avatar
  • 221
2 votes
0 answers
71 views

Simultaneous computation of the three Weber modular functions

Recall that the three classical Weber modular functions are defined by $f(\tau)=e^{-\pi i/24}\eta((\tau+1)/2)/\eta(\tau)$, $f_1(\tau)=\eta(\tau/2)/\eta(\tau)$, and $f_2(\tau)=\sqrt{2}\eta(2\tau)/\eta(\...
Henri Cohen's user avatar
  • 13.1k
2 votes
0 answers
118 views

Computing coefficients of theta functions associated to quadratic forms

If we take an integral positive definite quadratic form $Q$ and set $\Theta_Q(z) = \sum_{k\geq 0}R_Q(k)e^{2\pi ikz}$, what are the most efficient algorithms to compute the $R_Q(k)$? I am aware e.g. of ...
a196884's user avatar
  • 323
1 vote
0 answers
583 views

Langlands program and complexity theory

Back when I was an undergraduate, I spent some time reading the about the modularity conjecture, but the details are fuzzy now. One of the motivations I imagined for the Langlands program was for ...
user321680's user avatar
0 votes
0 answers
172 views

An application of Koike's Trace Formula

Koike's Trace Formula states that \begin{equation} \mbox{Tr}((U_p^{\kappa})^n) = - \sum_{0 \leq u < \sqrt{p^n}\\ (u,p)=1}H(u^2-4p^n)\frac{\gamma(u)^\kappa}{\gamma(u)^2 - p^n}-1, \end{equation} ...
Cláudio da Silva Velasque's user avatar