Hölder continuous homomorphisms between infinite-dimensional Lie groups are smooth

Let f : G → H be a homomorphism between smooth Lie groups modelled on Mackey complete, locally convex real topological vector spaces. We show that if f is Hölder continuous at 1, then f is smooth. © 2005 Elsevier Inc. All rights reserved. MSC: 22E65 (main); 22E35, 26E15, 26E20, 26E30, 46S10, 46T20, 58C20