UDC 512.5
In 2005, Enochs, Jenda, and López-Romos extended the notion of perfect rings to
n
-perfect rings such that a ring is
n
-perfect if every flat module has projective dimension less or equal than
n
. Later, Jhilal and Mahdou defined a commutative unital ring
R
to be strongly
n
-perfect if any
R
-module of flat dimension less or equal than
n
has a projective dimension less or equal than
n
. Recently Purkait defined a ring
R
to be
n
-semiperfect if
R
¯
=
R
/
R
a
d
(
R
)
is semisimple and
n
-potents lift modulo
R
a
d
(
R
)
.
We study of three classes of rings, namely,
n
-perfect, strongly
n
-perfect, and
n
-semiperfect rings. We investigate these notions in several ring-theoretic structures with an aim of construction of new original families of examples satisfying the indicated properties and subject to various ring-theoretic properties.