I was asking myself if there exists a sort of canonical relation between the standard contact structure on $J^1 N$ and $J^1 M$, for an arbitrary submanifold $N$ of $M$.


My starting point is that, constructing the spaces of $k$-jets and their structures of smooth manifolds, it is remarked that, for any smooth manifold $P$:  

while, mapping $\phi\in C^\infty(M,N)$ to $J^k(P,\phi):J^k(P,M)\to J^k(P,N),\ j^k\_x f\mapsto j\_x^k (\phi\circ f)$, it is possible to define the covariant endofunctor $J^k(P,\cdot)$ of the category of smooth manifolds and maps,  

instead, it is possible only to define a contravariant functor $J^k(P,\cdot)$ from the category of diffeomorfisms to the category of smooth maps, by mapping $\phi\in\mathrm{Diffeo}(M,N)$ to $J^k(P,\phi):J^k(P,N)\to J^k(P,M),\ j^k\_x f\mapsto j^k\_{\phi^{-1}(x)} (f\circ\phi)$.


So it seems to me that this is not the way to relate the $1$-jets space of a manifold $M$ and that of one of its submanifold $N$.  

But I imagine that the entire information on $J^1 N$ is already contained in $J^1 M$, even if I do not see (up to now) how to extract it with some invariantly defined procedure 


My question is:



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> Given a submanifold $N$ of $M$, under what conditions is there a sort of canonical relation between the standard contact structures of $J^1 N$ and $J^1 M$? and in what terms is it expressed?
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if $N$ is a submanifold of $M$, then what is the relation between $J^1 N$ and $J^1 M$?
Well, the short answer is that, when $N$ is a submanifold of $M$, the contact manifold $J^1(N)$ is a subquotient of $J^1(M)$. The point is that restriction of germs of functions to submanifolds implies that, if $S\subset J^1(M)$ is the submanifold consisting of those $1$-jets with source a point of $N$, then the canonical submersion $S\to J^1(N)$ induced by restriction of germs has the property that it pulls back the canonical contact form on $J^1(N)$ to be the pullback to $S$ of the canonical contact form on $J^1(M)$. I don't know that there's much more to say than that.


