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Counterexamples for Türkelli's Modification on Malle's Conjecture

Jiuya Wang

TL;DR

The paper presents counterexamples to Türkelli's modification of Malle's conjecture, showing that the proposed $b$-constant $b_T(G,k)$ can differ from the true $b(G,k)$ and from Malle's original prediction, with explicit instances where function-field and number-field constants diverge. It analyzes the embedding problem of cyclotomic extensions, introduces a refined, invariant-sensitive framework that partitions G-extensions by cyclotomic data, and defines a lifting-based counting function $N_{Q,\pi,\phi}(G^{inv},X)$ to capture these subtleties. The authors compute $b$-constants for specific wreath-product groups over both number fields and function fields, demonstrating infinite families where $b_T$ and $b_M$ bound the true constant in different ways and where $b$-constants diverge across base fields. They propose a refined Malle conjecture that aggregates over finitely many embedding data pairs $(\pi,\phi)$ and accommodates function-field behavior, supported by function-field results and recent advances on embedding problems. Overall, the work indicates that a universal, single-constant formulation of Malle’s conjecture is unlikely and motivates a composition-by-embedding approach to capture cyclotomic interactions and constants more accurately, potentially guiding future conjectures and proofs in both arithmetic and function-field contexts.

Abstract

We give counterexamples for the modification on Malle's Conjecture given by Türkelli. Türkelli's modification on Malle's conjecture is inspired by an analogue of Malle's conjecture over a function field. As a consequence, our counterexamples demonstrate that the $b$ constant can differ between function fields and number fields. We also show that Klüners' counterexamples give counterexamples for a natural extension of Malle's conjecture to counting number fields by product of ramified primes. We then propose a refined version of Malle's conjecture which implies a new conjectural value for the constant $b$ for number fields.

Counterexamples for Türkelli's Modification on Malle's Conjecture

TL;DR

The paper presents counterexamples to Türkelli's modification of Malle's conjecture, showing that the proposed -constant can differ from the true and from Malle's original prediction, with explicit instances where function-field and number-field constants diverge. It analyzes the embedding problem of cyclotomic extensions, introduces a refined, invariant-sensitive framework that partitions G-extensions by cyclotomic data, and defines a lifting-based counting function to capture these subtleties. The authors compute -constants for specific wreath-product groups over both number fields and function fields, demonstrating infinite families where and bound the true constant in different ways and where -constants diverge across base fields. They propose a refined Malle conjecture that aggregates over finitely many embedding data pairs and accommodates function-field behavior, supported by function-field results and recent advances on embedding problems. Overall, the work indicates that a universal, single-constant formulation of Malle’s conjecture is unlikely and motivates a composition-by-embedding approach to capture cyclotomic interactions and constants more accurately, potentially guiding future conjectures and proofs in both arithmetic and function-field contexts.

Abstract

We give counterexamples for the modification on Malle's Conjecture given by Türkelli. Türkelli's modification on Malle's conjecture is inspired by an analogue of Malle's conjecture over a function field. As a consequence, our counterexamples demonstrate that the constant can differ between function fields and number fields. We also show that Klüners' counterexamples give counterexamples for a natural extension of Malle's conjecture to counting number fields by product of ramified primes. We then propose a refined version of Malle's conjecture which implies a new conjectural value for the constant for number fields.

Paper Structure

This paper contains 16 sections, 21 theorems, 81 equations.

Key Result

Theorem 1.3

Let $\ell$ be an odd prime number and $d = \prod_i p_i^{r_i} \neq 2$ where $p_i$ are all prime numbers. Let $G = C_{\ell} \wr C_{d}\subset S_{\ell d}$ with $(|G|, \operatorname{char}(Q)) = 1$, $\mathop{\mathrm{Gal}}\nolimits({\mathbb{F}}_q(t)(\mu_{\ell})/{\mathbb{F}}_q(t)) \simeq \mathop{\mathrm{Gal As a consequence, there exists $G\subset S_n$ such that $\mathop{\mathrm{Gal}}\nolimits({\mathbb{F}

Theorems & Definitions (65)

  • Conjecture 1: Malle's Conjecture over Number Fields, Mal02Mal04
  • Conjecture 2: Malle's Conjecture over Function Field
  • Conjecture 3: Türkelli's Modification turkelli2015connected
  • Example 1.1
  • Theorem 1.3
  • Conjecture 4
  • Conjecture 5: Generalized Malle's Conjecture
  • Definition 1.4: Concentrated Group, ALOWW
  • Definition 1.5: Big Fiber
  • Theorem 1.6
  • ...and 55 more