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We prove that the handlebody subgroup of the Torelli group of an orientable surface is generated by genus one BP-maps. As an application, we give a normal generating set for the handlebody subgroup of the level $d$ mapping class group of an…

Geometric Topology · Mathematics 2016-07-25 Genki Omori

We show that the mapping class group of a closed oriented surface of genus at least three is generated by 3 elements of order 3 and by 4 elements of order 4. Note that the mapping class group cannot be generated by finitely many torsion…

Geometric Topology · Mathematics 2009-12-17 Naoyuki Monden

Let $N_g$ be a closed, connected, nonorientable surface of genus $g$. We prove that for $g \ge 13$, the mapping class group $\text{Mod}(N_g)$ can be generated by exactly two elements. This improves the previously known bound of $g \ge 19$.

Geometric Topology · Mathematics 2026-05-14 Berkay Aybak , Hasan Ozden

Let $\textrm{Mod}(N_{g, p})$ denote the mapping class group of a nonorientable surface of genus $g$ with $p$ punctures. For $g\geq14$, we show that $\textrm{Mod}(N_{g, p})$ can be generated by five elements or by six involutions.

Geometric Topology · Mathematics 2023-02-06 Tulin Altunoz , Mehmetcik Pamuk , Oguz Yildiz

Let a and b be two simple closed curves on an orientable surface S such that their geometric intersection number is greater than 1. It is known that the group generated by corresponding Dehn twists t_a and t_b is isomorphic to the free…

Geometric Topology · Mathematics 2016-08-18 Michal Stukow

Let $S(n)$, for $n \in \mathbb{N}$, be the infinite-type surface of infinite genus with $n$ ends, each accumulated by genus. Although the mapping class groups of these surfaces are not countably generated,they are Polish groups and hence…

Geometric Topology · Mathematics 2026-05-21 Tülin Altunöz , Celal Can Bellek , Emir Gül , Mehmetcik Pamuk , Oğuz Yıldız

The level $2$ mapping class group of an orientable closed surface can be generated by squares of Dehn twists about non-separating curves. On the other hand, the level $2$ mapping class group $\mathcal{M}_2(N_g)$ of a non-orientable closed…

Geometric Topology · Mathematics 2023-03-10 Nao Imoto , Ryoma Kobayashi

We show that the normal closure of any periodic element of the mapping class group of a non-orientable surface whose order is greater than 2 contains the commutator subgroup, which for $g\geq 7$ is equal to the twist subgroup, and provide…

Geometric Topology · Mathematics 2019-03-26 Marta Leśniak

A minimal (by inclusion) generating set for the algebra of semi-invariants of a quiver of dimension (2,...,2) is established over an infinite field of arbitrary characteristic. The mentioned generating set consists of the determinants of…

Representation Theory · Mathematics 2011-07-13 A. A. Lopatin

We give an infinite presentation for the mapping class group of a non-orientable surface. The generating set consists of all Dehn twists and all crosscap pushing maps along simple loops.

Geometric Topology · Mathematics 2017-02-08 Genki Omori

Let $N_{g,n}$ denote the closed non-orientable surface of genus $g$ with $n$ punctures and let ${\mathcal N}_{g,n}$ denote the mapping class group of $N_{g,n}$. Szepietowski showed that ${\mathcal N}_{g,n}$ is generated by finitely many…

Geometric Topology · Mathematics 2022-12-21 Kazuya Yoshihara

The present paper are the notes of a mini-course addressed mainly to non-experts. It purpose it to provide a first approach to the theory of mapping class groups of non-orientable surfaces.

Geometric Topology · Mathematics 2014-10-07 Luis Paris

The existence of an infinite simple boundedly generated 2-generated group and the existence of a boundedly simple 2-generated group containing a free non-cyclic subgroup are proved.

Group Theory · Mathematics 2022-03-28 Alexey Muranov

Let $N_{g,n}$ be a genus $g$ compact non-orientable surface with $n$ boundaries. We explain about relations on the level $d$ mapping class group $\mathcal{M}_d(N_{g,0})$ of $N_{g,0}$ and the level $d$ principal congruence subgroup…

Geometric Topology · Mathematics 2024-04-17 Ryoma Kobayashi

In this article, we study the normal generation of the mapping class group. We first show that a mapping class is a normal generator if its restriction on the invariant subsurface normally generates the (pure) mapping class group of the…

Geometric Topology · Mathematics 2023-10-10 Hyungryul Baik , Dongryul M. Kim , Chenxi Wu

We prove that the mapping class group of a closed connected orientable surface of genus $g$ is generated by two elements of order $g$ for $g\geq 6$. Moreover, for $g\geq 7$ we found a generating set of two elements, of order $g$ and $g'$…

Geometric Topology · Mathematics 2020-03-13 Oguz Yildiz

In this chapter, we discuss normal generators for mapping class groups of surfaces. Especially, we focus on the relation between normal generation of a mapping class with its asymptotic translation lengths on the Teichm\"uller space and the…

Geometric Topology · Mathematics 2026-04-13 Hyungryul Baik , Dongryul M. Kim

Let $S(n)$ be the infinite-type surface with infinite genus and $n \in \mathbb{N}$ ends, all of which are accumulated by genus. The mapping class group of this surface, $\mod(S(n))$, is a Polish group that is not countably generated, but it…

Geometric Topology · Mathematics 2025-12-22 Tülin Altunöz , Celal Can Bellek , Emir Gül , Mehmetcik Pamuk , Oğuz Yıldız

Crosscap slide is a homeomorphism of a nonorientable surface of genus at least 2, which was introduced under the name Y-homeomorphism by Lickorish as an example of an element of the mapping class group which cannot be expressed as a product…

Geometric Topology · Mathematics 2017-02-09 Blazej Szepietowski

We show that the mapping class group of any closed connected orientable surface of genus at least five is generated by only two commutators, and if the genus is three or four, by three commutators.

Geometric Topology · Mathematics 2019-08-30 R. Inanc Baykur , Mustafa Korkmaz