New York City Category Theory Seminar
Something Old, Something New, Something Borrowed, ...
Next F.E.J. Linton • Wesleyan Univ. Math/CS Emeritus

  Now, given a section f for the projection p from this double-cover to Heath’s V-space, consider the set
X = {xR : f is continuous in a neighborhood of (x, 0)}.  
  For such x, by continuity, there are layer λ and real ε > 0 such that f carries Vε(x) homeomorphically onto Vελ(x) (the full basic broken V of height ε centered at f(x, 0) = (x, 0, λ)) .