2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/63023Consider the $2n$-dimensional closed ball $B$ of radius 1 in the $2n$-dimensional symplectic cylinder $Z = D \times R^{2n-2}$ over the closed disc $D$ of radius 1. We construct for each $ε>0$ a Hamiltonian deformation $ϕ$ of $B$ in $Z$ of energy less than $ε$ such that the area of each intersection of $ϕ(B)$ with the disc $D \times \{x\}$, $x \in R^{2n-2}$, is less than $ε$.27 pages, 9 figuresSymplectic Geometry53D35text