Bounding the sup-norm of automorphic forms

 
J. Jorgenson and J. Kramer

 
 
  In this paper we give optimal bounds for the ratio of the canonical (or Arakelov) metric and the hyperbolic (or Poincaré) metric of quotient spaces of the upper half-plane by any Fuchsian subgroup of the first kind in PSL_{2}(R).
 
  Comments : The paper is going to appear in GAFA.