New York City Category Theory Seminar Something Old, Something New, Something Borrowed, ...
F.E.J. Linton • Wesleyan Univ. Math/CS Emeritus
Heath’s V-space is just the upper half-plane with an unusual topology,
in which all points above the
x-axis are open, and the basic open neighborhoods
of a point (x, 0)on
the x-axis are ... the various symmetric “open V ”s, with 45-degree fingers of arbitrary
equal non-zero lengths, as shown.