p. p. rings and generalized p. p. rings (Q5957263)

A ring \(R\) with identity is right p.p. if \(xR\) is projective for any \(x\) in \(R\), and \(R\) is generalized right p.p. if for any \(x\) in \(R\) there is a positive integer \(n\) such that \(x^nR\) is projective. The authors study subrings and extensions of p.p. rings and generalized p.p. rings. Some interesting examples are also given.