Let
Br(0)={(x,y)∈R2:x2+y2<r2},
B=B1(0), and
C={(x,y)∈R2:x2+y2=1}
Let D=B∪C.
(i) State the Brouwer fixed point theorem on the plane.
(ii) Show that the Brouwer fixed point theorem on the plane is equivalent to the nonexistence of a continuous map F:D→C such that F(p)=p for each p∈C.
(iii) Let G:D→R2 be continuous, 0<ϵ<1 and suppose that
∣p−G(p)∣<ϵ
for each p∈C. Using the Brouwer fixed point theorem or otherwise, prove that
B1−ϵ(0)⊆G(B)
[Hint: argue by contradiction.]
(iv) Let q∈B. Does there exist a continuous map H:D→R2\{q} such that H(p)=p for each p∈C ? Justify your answer.