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Katharina Müller

Publications and source records attributed to Katharina Müller.

31 records · Page 2Linked to original sources
arXiv2024

On ordinary isogeny graphs with level structure

Let $l$ and $p$ be two distinct prime numbers. We study $l$-isogeny graphs of ordinary elliptic curves defined over a finite field of characteristic $p$, together with a level structure. Firstly, we show that as the level varies over all $p$-powers, the graphs form an Iwasawa-theoretic abelian $p$-tower, which can be regarded as a graph-theoretical analogue of the Igusa tower of modular curves. Secondly, we study the structure of the crater of these graphs, generalizing previous results on volcano graphs. Finally, we solve an inverse problem of graphs arising from the crater of $l$-isogeny graphs with level structures, partially generalizing a recent result of Bambury, Campagna and Pazuki.

math.NT↗
arXiv2023

On the Zeta functions of supersingular isogeny graphs and modular curves

Let $p$ and $q$ be distinct prime numbers, with $q\equiv 1\pmod{12}$. Let $N$ be a positive integer that is coprime to $pq$. We prove a formula relating the Hasse--Weil zeta function of the modular curve $X_0(qN)_{\mathbb{F}_q}$ to the Ihara zeta function of the $p$-isogeny graphs of supersingular elliptic curves defined over $\overline{\mathbb{F}_q}$ equipped with a $Γ_0(N)$-level structure. When $N=1$, this recovers a result of Sugiyama.

math.NT↗
arXiv2023

On the non-commutative Iwasawa main conjecture for voltage covers of graphs

Let $p$ be a rational prime, and let $X$ be a connected finite graph. In this article we study voltage covers $X_\infty$ of $X$ attached to a voltage assignment $α$ which takes values in some uniform $p$-adic Lie group $G$. We formulate and prove an Iwasawa main conjecture for the projective limit of the Picard groups $\text{Pic}(X_n)$ of the intermediate voltage covers $X_n$, ${n \in \mathbb{N}}$, and we prove one inclusion of a main conjecture for the projective limit of the Jacobians $J(X_n)$. Moreover, we study the $\mathfrak{M}_H(G)$-property of $\mathbb{Z}_p[[G]]$-modules and prove a necessary condition for this property which involves the $μ$-invariants of $\mathbb{Z}_p$-subcovers ${Y \subseteq X_\infty}$ of $X$. If the dimension of $G$ is equal to 2, then this condition is also sufficient.

math.NT↗
arXiv2023

On the Iwasawa invariants of BDP Selmer groups and BDP P-adic L-fucntions

Let $p$ be an odd prime. Let $f_1$ and $f_2$ be weight-two Hecke eigen-cuspforms with isomorphic residual Galois representations at $p$. Greenberg--Vatsal and Emerton--Pollack--Weston showed that if $p$ is a good ordinary prime for the two forms, the Iwasawa invariants of their $p$-primary Selmer groups and $p$-adic $L$-functions over the cyclotomic $\mathbb{Z}_p$-extension of $\mathbb{Q}$ are closely related. The goal of this article is to generalize these results to the anticyclotomic setting. More precisely, let $K$ be an imaginary quadratic field where $p$ splits. Suppose that the generalized Heegner hypothesis holds with respect to both $(f_1,K)$ and $(f_2,K)$. We study relations between the Iwasawa invariants of the BDP Selmer groups and the BDP $p$-adic $L$-functions of $f_1$ and $f_2$.

math.NT↗
arXiv2022

On the growth of the Jacobian in $Z_p^l$-voltage covers of graphs

We investigate the growth of the $p$-part of the Jacobians in voltage covers of finite connected multigraphs, where the voltage group is isomorphic to $\mathbb{Z}_p^l$ for some ${l \ge 2}$, and we study analogues of a conjecture of Greenberg on the growth of class numbers in multiple $\mathbb{Z}_p$-extensions of number fields. Moreover we prove an Iwasawa main conjecture in this setting, and we study the variation of (generalised) Iwasawa invariants as one runs over the $\mathbb{Z}_p^l$-covers of a fixed finite graph $X$. We discuss many examples; in particular, we construct examples with non-trivial Iwasawa invariants.

math.NT↗
arXiv2022

Fine Selmer groups of modular forms

We compare the Iwasawa invariants of fine Selmer groups of $p$-adic Galois representations over admissible $p$-adic Lie extensions of a number field $K$ to the Iwasawa invariants of ideal class groups along these Lie extensions. More precisely, let $K$ be a number field, let $V$ be a $p$-adic representation of the absolute Galois group $G_K$ of $K$, and choose a $G_K$-invariant lattice ${T \subseteq V}$. We study the fine Selmer groups of ${A = V/T}$ over suitable $p$-adic Lie extensions $K_\infty/K$, comparing their corank and $μ$-invariant to the corank and the $μ$-invariant of the Iwasawa module of ideal class groups in $K_\infty/K$. In the second part of the article, we compare the Iwasawa $μ$- and $l_0$-invariants of the fine Selmer groups of CM modular forms on the one hand and the Iwasawa invariants of ideal class groups on the other hand over trivialising multiple $\mathbb{Z}_p$-extensions of $K$.

math.NT↗
arXiv2022

Which programming languages do hackers use? A survey at the German Chaos Computer Club

There are numerous articles about the programming languages most commonly used by hackers. Among them, however, there are hardly any scientific studies. One reason might be that hackers mainly operate anonymously and are difficult to reach. This paper aims to shed light on this interesting and relevant research question. In order to find answers, we conducted a survey among the members of the German Chaos Computer Club. As one of the world's largest organisations for information security and hacking, the club provides a good basis for our study. We examine the question of which programming languages are used by hackers as well as the importance of the programming language for their work. The paper offers first insights into the topic and can provide a starting point for further research.

cs.CR↗
arXiv2022

Fine Selmer groups and ideal class groups

Let $K_\infty/K$ be a uniform $p$-adic Lie extension. We compare several arithmetic invariants of Iwasawa modules of ideal class groups on the one side and fine Selmer groups of abelian varieties on the other side. If $K_\infty$ contains sufficiently many $p$-power torsion points of $A$, then we can compare the ranks and the Iwasawa $μ$-invariants of these modules over the Iwasawa algebra. In several special cases (e.g. multiple $\mathbb{Z}_p$-extensions), we can also prove relations between suitable generalisations of the Iwasawa $λ$-invariant of the two types of Iwasawa modules. In the literature, different kinds of Iwasawa $λ$-invariants have been introduced for ideal class groups and Selmer groups. We define analogues of both concepts for fine Selmer groups and compare the resulting invariants. In order to obtain some of our main results, we prove new asymptotic formulas for the growth of ideal class groups and fine Selmer groups in multiple $\mathbb{Z}_p$-extensions.

math.NT↗
arXiv2021

Fine Selmer groups of congruent $p$-adic Galois representations

We compare the Pontryagin duals of fine Selmer groups of two congruent $p$-adic Galois representations over admissible pro-$p$, $p$-adic Lie extensions $K_\infty$ of number fields $K$. We prove that in several natural settings the $π$-primary submodules of the Pontryagin duals are pseudo-isomorphic over the Iwasawa algebra; if the coranks of the fine Selmer groups are not equal, then we can still prove inequalities between the $μ$-invariants. In the special case of a $\mathbb{Z}_p$-extension $K_\infty/K$, we also compare the Iwasawa $λ$-invariants of the fine Selmer groups, even in situations where the $μ$-invariants are non-zero. Finally, we prove similar results for certain abelian non-$p$-extensions.

math.NT↗
arXiv2021

The Main Conjecture for Imaginary quadratic fields for the split prime $p=2$

Let $\mathbb{K}$ be an imaginary quadratic field such that $2$ splits into two primes $\mathfrak{p}$ and $\bar{\mathfrak{p}}$. Let $\mathbb{K}_{\infty}$ be the unique $\mathbb{Z}_2$-extension of $\mathbb{K}$ unramified outside $\mathfrak{p}$. Let $\mathfrak{f}$ be an ideal coprime to $\mathfrak{p}$ and $\mathbb{L}$ be an arbitrary extension of $\mathbb{K}$ contained in the ray class field $\mathbb{K}(\mathfrak{p}^2\mathfrak{f})$. Let $\mathbb{L}_{\infty}=\mathbb{K}_{\infty}\mathbb{L}$ and let $\mathbb{M}$ be the maximal $p$-abelian, $\mathfrak{p}$-ramified extension of $\mathbb{L}_{\infty}$. We set $X=Gal(\mathbb{M}/\mathbb{L}_{\infty})$. In this paper we prove the Iwasawa main conjecture for the module $X$.

math.NT↗
arXiv2021

$2$-class groups of cyclotomic towers of imaginary biquadratic fields and applications

Let $d$ be a positive square-free integer. In this paper we shall investigate the structure of the $2$-class group of the cyclotomic $\mathbb{Z}_2$-extension of the imaginary biquadratic number field $\mathbb{Q}(\sqrt{d},\sqrt{-1})$. Furthermore, we deduce the structure of the $2$-class group of cyclotomic $\mathbb{Z}_2$-extension of $\mathbb{Q}(\sqrt{-d})$.

math.NT↗
arXiv2010

Precision measurements with jets and particles at HERA

Inclusive jet and multijet cross sections measured in ep collisions in different kinematic regions by the H1 and ZEUS experiments are shown. The measurements are used to extract the strong coupling alpha_s as a function of the scale and at the mass of the Z-boson. Results from prompt photon production in comparison with pQCD calculations are shown in photoproduction and deep-inelastic scattering. Other topics address scaled momentum distributions of charged particles, a measurement of the transverse momenta of charged particles and the first measurement of the charge asymmetry at HERA.

hep-ex↗