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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeMar 1st 2012
• (edited Mar 1st 2012)

I have been expanding and polishing the entry Heisenberg group.

This had existed in bad shape for quite a while, but now it’s maybe getting into better shape.

I tried to spend some sentences on issues which I find are rarely highlighted appropriately in the literature. So there is discussion now of the fact that

• there are different Lie groups for a given Heisenberg Lie algebra,

• and the appearance of an “$i$” in $[q,p] = i$ may be all understood as not picking the simply conncted ones of these;

I also added remarks on the relation to Poisson brackets, and symplectomorphisms.

In this context: either I am dreaming, or there is a mistake in the Wikipedia entry Poisson bracket - Lie algebra.

There it says that the Poisson bracket is the Lie algebra of the group of symplectomorphisms. But instead, it is the Lie algebra of a central extension of the group of Hamiltonian symplectomorphisms.