A new tool to study reducibility of a weak symplectic form to a constant one is introduced and used to prove a version of the Darboux theorem more general than previous ones. More precisely, at each point of the considered manifold a Banach space is associated to the symplectic form (dual of the phase space with respect to the symplectic form), and it is shown that the Darboux theorem holds if ...

The multi-symplectic form for Hamiltonian PDEs leads to a general framework for geometric numerical schemes that preserve a discrete version of the conservation of symplecticity. The cases for systems or PDEs with dissipation terms has never been extended. In this paper, we suggest a new extension for generalizing the multi-symplectic form for Hamiltonian systems to systems with dissipation whi...

A number of conservative PDEs, like various wave equations, allow for a multi-symplectic formulation which can be viewed as a generalization of the symplectic structure of Hamiltonian ODEs. We show that Gauss-Legendre collocation in space and time leads to multi-symplectic integrators, i.e., to numerical methods that preserve a symplectic conservation law similar to the conservation of symplect...

A remarkable theorem of Donaldson [D] says that a symplectic 4manifold admits a Lefschetz pencil by symplectic surfaces. Given a Lefschetz pencil on a 4-manifold X, one can blow up points at the base locus to get a Lefschetz fibration of X over S, which admits a nice handlebody decomposition and can be described by geometric monodromy representation into the mapping class group of a regular fib...

Hyperkähler embeddings and holomorphic symplectic geometry I. 0. Introduction. In this paper we are studying complex analytic subvarieties of a given Kähler manifold which is endowed with a holomorphic symplectic structure. By Calabi-Yau theorem, the holomorphically symplectic Kähler mani-folds can be supplied with a Ricci-flat Riemannian metric. This implies that such manifolds are hyperkähler...

Let M be a closed oriented smooth 4−manifold admitting symplectic structures. If M is minimal and has b + = 1, we prove that there is a unique symplectic canonical class up to sign, and any real second cohomology class of positive square is represented by symplectic forms. Similar results hold when M is not minimal. §1. Introduction Let M be a smooth, closed oriented 4−manifold. An orientation-...

The easiest example of a symplectic manifold is the standard sym-plectic vector space V := R 2n with coordinates (q 1 ; p 1 ; :::; q n ; p n) and symplectic form ! = n X j=1 dq j ^ dp j : The basic feature of ! is that it is a closed non-degenerate 2-form on R 2n. In particular it gives a natural indentiication of V with its dual V v ! !(v; :): As an auxiliary structure we also use the standard...

Given a Lagrangian submanifold in a symplectic manifold and a Morse function on the submanifold, we show that there is an isotopic Morse function and a symplectic Lefschetz pencil on the manifold extending the Morse function to the whole manifold. From this construction we define a sequence of symplectic invariants classifying the isotopy classes of Lagrangian spheres in a symplectic 4-manifold.

In this paper we introduce Symplectic Grassmann codes, in analogy to ordinary Grassmann codes and Orthogonal Grassmann codes, as projective codes defined by symplectic Grassmannians. Lagrangian–Grassmannian codes are a special class of Symplectic Grassmann codes. We describe all the parameters of line Symplectic Grassmann codes and we provide the full weight enumerator for the Lagrangian–Grassm...

The first part of this paper deals with electrical networks and symplectic reductions. We consider two operations on electrical networks (the “trace map” and the “gluing map”) and show that they correspond to symplectic reductions. We also give several general properties about symplectic reductions, in particular we study the singularities of symplectic reductions when considered as rational ma...