- #36

jbergman

- 410

- 168

Good point.cianfa72 said:Just to avoid confusion, your function ##f## is given in ##(U_2,\phi)## chart as ##f(u,v)=v##. The level set of ##f(u,v)= \text{c}## is the set of points ##A \cup B## where $$A = \begin {cases} (x, c) & \text{if } 0< x< \frac12 \\ (x, -c) & \text{if } \frac12 < x < 1 \end {cases}$$ and ##B=[0,c]=[1,-c]##.

However such a level set is not a single leaf of the foliation given by "circles" going around twice around the strip for ##c \neq 0##.