There are three questions:

- Please let me know your proof of the following theorem:

If $CP^3$ can be immersed in $R^8$ with an Euler class $W_{2}(\nu)$ for the normal bundle of $CP^3$ respect to $R^8$ then $$\int_{CP^3} \!W_{{2}} \left( \nu \right) c^2$$ is divisible by 3.

Where $c$ is the cohomological generator of $CP^3$.

- What is the exact value of the integral

$$\int_{CP^3} \!W_{{2}} \left( \nu \right) c^2$$

- It is possible to have an immersion of $CP^3$ in $R^8$?

Many thanks.