Chazal, F.Cohen-Steiner, D.Gershon Elber and Nicholas Patrikalakis and Pere Brunet2016-02-172016-02-1720043-905673-55-X1811-7783https://doi.org/10.2312/sm.20041380In this paper, we give a very simple and purely topological condition for two surfaces to be isotopic. This work is motivated by the problem of surface approximation. Applications to implicit surfaces are given, as well as connections with the well-known concepts of medial axis and local feature size.10.2312/sm.2004138093-99