A trivalent triangle group is a triangle of groups with the trivial face group and edge groups isomorphic to Z/3Z. In this talk, I will introduce the weighted L2-cohomology of Coxeter groups originally defined by Davis, Dymara, Januszkiewicz and Okun and use it to show virtual fibration and consequently incoherence of certain trivalent triangle groups acting on hyperbolic buildings.
