The fundamental group of a triangular algebra without double bypasses

Patrick Le Meur (1)

1 I3M - Institut de Mathématiques et de Modélisation de Montpellier

Let A be a basic connected finite dimensional algebra over a field k and let Q be the ordinary quiver of A. To any presentation of A with Q and admissible relations, R. Martinez-Villa and J. A. de La Pena have associated a group called the fundamental group of this presentation. There may exist different presentations of A with non isomorphic fundamental groups. In this note, we show that if the field k has characteristic zero, if Q has no oriented cycles and if Q has no double bypasses then there exists a privileged presentation of A such that the fundamental group of any other presentation is the quotient of the fundamental group of this privileged presentation.

Mots clés: fundamental group; automorphisms of algebras

Domaines: Théorie des représentations [math.RT]

Patrick Le Meur. The fundamental group of a triangular algebra without double bypasses. Comptes rendus de l'Académie des sciences. Série I, Mathématique, 2005, 341 (4), pp.211--216. ⟨10.1016/j.crma.2005.07.004⟩. ⟨hal-00004477v3⟩