A 2001 paper by F.A. Muller proposes "ARC" (a modified form of Ackermann set theory) as a foundations of mathematics, and argues that it founds category theory more naturally and/or conveniently than other, competing approaches to set theory. Muller's approach looks interesting. I was wondering
- Has it gained many adherents?
- Has it been used as a basis for any foundational works since it was first proposed?
- Have any issues with ARC come to light in the past 12 years?