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

Two stacked upper ½-planes   If each finger height exceeds half the distance between the points on the x-axis, the two Vs will intersect nontrivially, and otherwise not; this is worth remembering for later.

  By the way, when Vε(x) and Vε'(y) do meet (i.e., when ε > ½|x−y| < ε' ), it’s at the point (½(x+y), ½|x−y|) .

  For our double cover, we look to the connected double cover of the circle for motivation ...
Heath“s V-space as Base