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mma
May19-11, 02:34 AM
The canonical symplectic form on T^*M is the exterior derivative of the tautological 1-form:
\omega=d\alpha
where \alpha_p(X):=p(d\pi(X)) is the tautological 1-form.

Let Y \in T_pT^*M a vertical vector, that is d\pi(Y)=0.

It's trivial to prove using canonical coordinates that for all X \in T_pT^*M
\omega(X,Y) = y(d\pi(X))
where y \in T_{\pi(p)}^*M such that for any differentiable function f: T^*M \to \mathbb R Y(f)=\left. \frac{df(p+ty)}{dt}\right|_{t=0}.

But how can it be proved in a coordinate-free manner?

mma
May20-11, 02:19 AM
Erratum.

The canonical symplectic form on T^*M is the exterior derivative of the tautological 1-form:
\omega=d\alpha


should be

The canonical symplectic form on T^*M is the negative of the exterior derivative of the tautological 1-form:
\omega=-d\alpha


Any idea?

quasar987
May20-11, 12:14 PM
Your question is giving me a headache, but have you looked in the book by Anna Canna Da Silva (first or second chapter I think)? There, she proves many properties of the tautological 1-form in coordinate free form.

mma
May20-11, 11:27 PM
Your question is giving me a headache, but have you looked in the book by Anna Canna Da Silva (first or second chapter I think)? There, she proves many properties of the tautological 1-form in coordinate free form.


Yes, I know (and like) da Silva's book, but I didn't find this in it. I give a better chance to the book of Libermann and Marle. Thanks anyway.

quasar987
May21-11, 01:22 PM
I didn't know about this book until now. Thanks.