Beschreibung (Langtext)

We examine three invariants for exact loops of Lagrangiansubmanifolds that are modelled on invariants introduced by LeonidPolterovich for loops of Hamiltonian symplectomorphisms. One ofthese is the minimal Hofer length in a given Hamiltonian isotopyclass. We determine the exact values of these invariants for loopsof projective Lagrangian planes. The proof uses the Gromovinvariants of an associated symplectic fibration over the 2-discwith a Lagrangian subbundle over the boundary. The last twochapters concern different topics and can be read completelyindependently.