2010/04/20 by Chen, Bo
#16G20 #16G70 #FOS: Mathematics #Representation Theory (math.RT)
paper · doi:10.48550/arxiv.1004.3472
A GR-segment for an artin algebra is a sequence of Gabriel-Roiter measures, which is closed under direct predecessors and successors. The number of the GR-segments indexed by natural numbers ℕ and integers ℤ probably relates to the representation types of artin algebras. Let k be an algebraically closed field and Q be a tame quiver (of type \widetilde\mathbbAn, \widetilde\mathbbDn, \widetilde𝔼6, \widetilde𝔼7, or \widetilde𝔼8). Let b be the number of the isomorphism classes of the exceptional quasi-simple modules over the path algebra Λ=kQ. We show that the number of the ℕ- and ℤ-indexed GR-segments in the central part for Q is bounded by b+1. Therefore, there are at most b+3 GR segments.