Bourbaki

Exercise 1, § 3

General Topology, VI

Let ff be the mapping of S2S_2 into R4\mathbf{R}^4 such that

f(x1,x2,x3)=(x12−x22,x1x2,x1x3,x2x3). f(x_1, x_2, x_3) = (x_1^2 - x_2^2, x_1 x_2, x_1 x_3, x_2 x_3).
This function has the same value at diametrically opposite points of S2S_2. Show that on passing to the quotient it defines a homeomorphism of P2P_2 onto a subspace of R4\mathbf{R}^4.

Show likewise that the mapping gg of S3S_3 into R6\mathbf{R}^6 defined by

g(x1,x2,x3,x4)=(x12−x22,x1x2,x1x3+x2x4,x32−x42,x3x4,x1x4−x2x3) g(x_1, x_2, x_3, x_4) = (x_1^2 - x_2^2, x_1 x_2, x_1 x_3 + x_2 x_4, x_3^2 - x_4^2, x_3 x_4, x_1 x_4 - x_2 x_3)
defines, on passing to the quotient, a homeomorphism of P3P_3 into R6\mathbf{R}^6.

Solution

No solution has been written yet.

Transcribed from the printed volume. Not translated.