- [Infinite-dimensional Lie groups](//ams.org/msc/msc2010.html?s=22E65); e.g. [locally convex groups](//ams.org/mathscinet-getitem?mr=2261066), [pro-Lie groups](//ams.org/mathscinet-getitem?mr=2337107), [ind-groups](//ams.org/mathscinet-getitem?mr=1925340).
- Central extensions thereof; e.g. [Virasoro group](//ams.org/mathscinet-getitem?mr=2362888).
- [Loop groups](//ams.org/msc/msc2010.html?s=22E67), [Current groups](//ams.org/msc/msc2010.html?s=81R10).
- Central extensions thereof, [Kac-Moody groups](//ams.org/msc/msc2010.html?s=20G44).