Universe n is not an n-Type
In basic MLTT with a sequence of univalent universes,
the first universe is not a set (i.e. not a 0-type).
This is one of the most basic consequences of univalence,
but already the next step is surprisingly difficult.
Several people have shown, in different ways, that the
second universe is not a 1-type, and the third is not
a 2-type.
In this talk, a proof for the general case is constructed.