Show that $X$ can be pulled apart from Z by an arbitrary small deformation

365 Views Asked by At

Let, $X$ be a compact submanifold of $Y$ and let $X$ intersect another submanifold $Z$. Assume that dim$X$ + dim$Z$ $<$ dim$Y$. Given $\epsilon> 0$ show that there exists a deformation $X_{t}=i_{t}(X)$ such that $X_{1}$ does not intersect Z and that $\mid x - i_{1}(x)\mid < \epsilon $ for all $x \in X $.

This is a problem from Guillemin and Pollack's Differential Topology book. Can anyone give me any suggestions on how to approach this problem?

1

There are 1 best solutions below

0
On BEST ANSWER

This is an immediate application of the Transversality Theorem. Because of the dimension hypothesis, the only way $i_t$ can be transverse to $Z$ is for the image to be disjoint from $Z$. Do this argument first when $Y=S=\Bbb R^N$ and let $i_s(x)=x+s$ for $s\in B(0,\epsilon)\subset\Bbb R^N$. Once you've written that out, go back to the case $Y\subset\Bbb R^N$ and use the $\epsilon$-neighborhood theorem as with a lot of the proofs in that section of the book.