Bulletin of the
Korean Mathematical Society BKMS

A $*$-ring $R$ is called $*$-regular if every principal one-sided ideal of $R$ is generated by a projection. In this note, several characterizations of $*$-regular rings are provided. In particular, it is shown that a matrix ring $M_n(R)$ is $*$-regular if and only if $R$ is regular and $1+x_1^*x_1+\cdots+x_{n-1}^*x_{n-1}$ is a unit for all $x_i$ of $R;$ which answers a question raised in the literature recently.

Keywords: $*$-regular ring, regular ring, matrix ring, GN property

MSC numbers: 16E50, 16W10