4 citations · 10 across the 10 of their papers we have counts for
6 papers · 1 filter
Curtis-Tits groups generalizing Kac-Moody groups of type
Rieuwert J. Blok, Corneliu Hoffman
In a previous paper we define a Curtis-Tits group as a certain generalization of a Kac-Moody group. We distinguish between orientable and non-orientable Curtis-Tits groups and iden…
Bass-Serre theory and counting rank two amalgams
Rieuwert J. Blok, Corneliu Hoffman
An amalgam of groups can be viewed as a Sudoku game inside a group. You are given a set of subgroups and their intersections and you need to decide what the largest group containin…
A classification of Curtis-Tits amalgams
Rieuwert Blok, Corneliu Hoffman
A celebrated theorem of Curtis and Tits on groups with finite BN-pair shows that roughly speaking these groups are determined by their local structure. This result was later extend…
On a Quasi-Phan Theorem for Orthogonal Groups
Corneliu Hoffman, Adam Roberts
This paper constructs a presentation for the orthogonal groups. The amalgam is contained in that constructed by Ralf Gramlich Hendrik Van Maldeghem and arXiv:0708.1583 but it's sho…
On a conjecture of Parker about Dessins d'Enfants
Corneliu Hoffman
This note is concerned with the disproof of the most general case of Parker's conjecture. The conjecture relates a certain group theoretic objects to the field of moduli of a Dessi…
Some Additive Combinatorics Problems in Matrix Rings
Ron Ferguson, Corneliu Hoffman, Florian Luca +2
We study the distribution of singular and unimodular matrices in sumsets in matrix rings over finite fields. We apply these results to estimate the largest prime divisor of the det…