Let R be a ring.A right R-module M is said to be minflat if for every minimal left ideal I the canonical homomorpism M_RI→M_RR is monic.R is called left minhereditary,if every minimal left ideal of R is projective.R is called left minregular,if every minimal left ideal of R is a direct summand.R is called mincoherent,if every minimal left ideal of R is finitely presented.Some characterizations of mininjective modules and minflat modules are given respectively.Minhereditary rings are characterized by mininjective modules,and minregular rings,and mincoherent r...