## Algebra & Number Theory

### Random matrices, the Cohen–Lenstra heuristics, and roots of unity

Derek Garton

#### Abstract

The Cohen–Lenstra–Martinet heuristics predict the frequency with which a fixed finite abelian group appears as an ideal class group of an extension of number fields, for certain sets of extensions of a base field. Recently, Malle found numerical evidence suggesting that their proposed frequency is incorrect when there are unexpected roots of unity in the base field of these extensions. Moreover, Malle proposed a new frequency, which is a much better match for his data. We present a random matrix heuristic (coming from function fields) that leads to a function field version of Malle’s conjecture (as well as generalizations of it).

#### Article information

Source
Algebra Number Theory, Volume 9, Number 1 (2015), 149-171.

Dates
Revised: 18 November 2014
Accepted: 25 December 2014
First available in Project Euclid: 16 November 2017

https://projecteuclid.org/euclid.ant/1510842261

Digital Object Identifier
doi:10.2140/ant.2015.9.149

Mathematical Reviews number (MathSciNet)
MR3317763

Zentralblatt MATH identifier
1326.11068

#### Citation

Garton, Derek. Random matrices, the Cohen–Lenstra heuristics, and roots of unity. Algebra Number Theory 9 (2015), no. 1, 149--171. doi:10.2140/ant.2015.9.149. https://projecteuclid.org/euclid.ant/1510842261

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