almost symplectic manifold

In differential geometry, an almost symplectic structure on a differentiable manifold $M$ is a two-form $\backslash omega$ on $M$ that is everywhere non-singular.{{citation|last=Ramanan|first=S.|isbn=0-8218-3702-8|location=Providence, RI|mr=2104612|page=189|publisher=American Mathematical Society|series=Graduate Studies in Mathematics|title=Global calculus|url=https://books.google.com/books?id=1INoRKtgndcC&pg=PA189|volume=65|year=2005}}. If in addition $\backslash omega$ is closed then it is a symplectic form.

An almost symplectic manifold is an Sp-structure; requiring $\backslash omega$ to be closed is an integrability condition.