8 citations · 8 across the 4 of their papers we have counts for
4 papers
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…
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…
A Quasi Curtis-Tits-Phan theorem for the symplectic group
Rieuwert J. Blok Corneliu Hoffman
We obtain the symplectic group $\SP(V)$ as the universal completion of an amalgam of low rank subgroups akin to Levi components. We let $\SP(V)$ act flag-transitively on the geomet…