Deligne's Letters to Breen

These letters were sent by Pierre Deligne to Larry Breen in February, 1994.

For more information on the construction, and applications to Poisson geometry, see the article
A Darboux theorem for Hamiltonian operators in the formal calculus of variations,
Duke J. Math. 111 (2002), 535-560.

For an extension of this construction to higher order n-groupoids, see the article
Lie theory for nilpotent L_∞ algebras,
to appear, Ann. of Math.

Please do not link to this URL, or refer to it in print, without written permission.