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Let $p:M\rightarrow N$ a surjective submersion of manifolds. Let $Y\subset N$ I want to prove that

$Y$ is a submanifold of $N$ if and only if $p^{-1}(Y)$ is a submanifold $M$.

I could prove that if $Y$ is a submanifold then $p^{-1}(Y)$ using the regular point theorem, but I could not prove the converse.

Any hint?

EQJ
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1 Answers1

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You can directly show that something is a manifold by exhibiting a system of charts for it with the right transition maps. Can you find a way of taking the system of charts on $p^{-1}(Y)$ and moving them over to give a system of charts on $Y$?

  • Well, the submersion are open, but I could not prove that the functions obtained for $Y$ are charts. – EQJ Oct 03 '17 at 04:09