I'm trying to understand the idea of 'formally' integrating a Lie algebra.
The universal enveloping algebra of a Lie algebra has a comultiplication on it, turning it into a Hopf algebra; if you take the set of all group-like elements of this algebra (i.e,. $\Delta g= g\otimes g$), you get a group which people call the 'formal' Lie group integrating the Lie algebra.
How does this 'formal' Lie group relate to the 'actual' Lie group (which there will be in a finite-dimensional setting) integrating the Lie algebra, e.g. how do you equip it with a topology, etc.? Is there a nice reference for this?