5 citations · 25 across the 16 of their papers we have counts for
17 papers
The level mapping class group of a compact non-orientable surface
Ryoma Kobayashi
Let be a genus compact non-orientable surface with boundaries. We explain about relations on the level mapping class group of $N_{g,0…
The level principal congruence subgroup of
Nao Imoto, Ryoma Kobayashi
The abelianization of the level principal congruence subgroup of was determined by Lee-Szczarba. By this result and a result of Tits, we ca…
Learning from Label Proportions with Instance-wise Consistency
Ryoma Kobayashi, Yusuke Mukuta, Tatsuya Harada
Learning from Label Proportions (LLP) is a weakly supervised learning method that aims to perform instance classification from training data consisting of pairs of bags containing…
On squares of Dehn twists about non-separating curves of a non-orientable closed surface
Nao Imoto, Ryoma Kobayashi
The level 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 mapping c…
Simple infinite presentations for the mapping class group of a compact non-orientable surface
Ryoma Kobayashi
Omori and the author have given an infinite presentation for the mapping class group of a compact non-orientable surface. In this paper, we give more simple infinite presentations…
An infinite presentation for the twist subgroup of the mapping class group of a compact non-orientable surface
Ryoma Kobayashi, Genki Omori
A finite presentation for the subgroup of the mapping class group of a compact non-orientable surface generated by all Dehn twists was given by Stukow. In this paper, we give an in…
Infinite presentations for fundamental groups of surfaces
Ryoma Kobayashi
For any finite type connected surface , we give an infinite presentation of the fundamental group of based at an interior point whose generators a…
Non-holomorphic Lefschetz fibrations with -sections
Noriyuki Hamada, Ryoma Kobayashi, Naoyuki Monden
We construct two types of non-holomorphic Lefschetz fibrations over with -sections ---hence, they are fiber sum indecomposable--- by giving the corresponding positive r…
An infinite presentation for the mapping class group of a non-orientable surface with boundary
Ryoma Kobayashi, Genki Omori
We give an infinite presentation for the mapping class group of a non-orientable surface with boundary components. The presentation is a generalization of the presentation given by…
A normal generating set for the Torelli group of a compact non-orientable surface
Ryoma Kobayashi
For a compact surface , let denote the Torelli group of . For a compact orientable surface , is generated by BSCC maps and BP maps. For a…
An infinite presentation for the mapping class group of a non-orientable surface
Genki Omori
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…
A finite generating set for the level 2 twist subgroup of the mapping class group of a closed non-orientable surface
Ryoma Kobayashi, Genki Omori
We obtain a finite generating set for the level 2 twist subgroup of the mapping class group of a closed non-orientable surface. The generating set consists of crosscap pushing maps…
A normal generating set for the Torelli group of a non-orientable closed surface
Susumu Hirose, Ryoma Kobayashi
For a closed surface , its Torelli group is the subgroup of the mapping class group of consisting of elements acting trivially on . When…
A finite presentation for the automorphism group of the first homology of a non-orientable surface over preserving the mod intersection form
Ryoma Kobayashi, Genki Omori
Let be the group of automorphisms on the first homology group with coefficient of a closed non-orientable surface $N…
A finite presentation of the level principal congruence subgroup of
Ryoma Kobayashi
It is known that the level principal congruence subgroup of has a finite generating set. In this paper, we give a finite presentation of the level princi…
Lefschetz pencils and finitely presented groups
Ryoma Kobayashi, Naoyuki Monden
In this paper, given a finitely presented group , we provide the explicit monodromy of a Lefschetz fibration with -sections whose total space has fundamental group by…
On genera of Lefschetz fibrations and finitely presented groups
Ryoma Kobayashi
It is known that every finitely presented group is the fundamental group of the total space of a Lefschetz fibration. In this paper, we give another proof which improves the result…