The homotopy type of the contactomorphism groups of tight contact $3$-manifolds, part I

Abstract: We compute the homotopy type of the space of embeddings of convex disks with Legendrian boundary into a tight contact $3$-manifold, whenever the sum of the absolute value of the rotation number of the boundary with the Thurston-Bennequin invariant is $-1$, proving that it is homotopy equivalent to the space of smooth embeddings. Using the same ideas it is also determined the homotopy type of the space of embeddings of convex spheres into a tight $3$-fold in terms of the space of smooth spheres. As a consequence we determine the homotopy type of the space of long Legendrian unknots, satisfying the previous condition, into a tight $3$-fold and also of the space of long transverse unknots with self-linking number $-1$, proving that these spaces are homotopy equivalent to the space of smooth long unknots. We also determine the homotopy type of the contactomorphism group of every universally tight handlebody, the standard $\NS^1\times\NS^2$ and every Legendrian fibration over a compact orientable surface with non-empty boundary, partially solving a conjecture due to E. Giroux. Finally, we show that the space of embeddings of Legendrian $(n,n)$-torus links with maximal Thurston-Bennequin invariant is homotopy equivalent to $\U(2)\times K(\mathcal{M}_n,1)$, where $\mathcal{M}_n$ is the mapping class group of the $2$-sphere with $n$-holes.