The Gabriel–Roiter measure for

Let k be an algebraically closed field. Let Λ be a tame hereditary k-algebra of type and δ be the minimal radical vector, which corresponds to the minimal positive imaginary root of the corresponding affine Lie algebra. We wish to investigate the Gabriel–Roiter measures of the indecomposable modules with dimension vector δ, which are very important when comparing (computing) the Gabriel–Roiter measures of regular modules. We will also give some relevant examples.