摘要:This paper contains results on self-circumferences of convex gures in the frameworksof norms and (more general) also of gauges. Let (n) denote the self-circumference of a regularpolygon with n sides in a normed plane. We will show that (n) is monotonically increasing from 6to 2 if n is twice an odd number, and monotonically decreasing from 8 to 2 if n is twice an evennumber. Calculations of self-circumferences for the case that n is odd as well as inequalities for theself-circumference of some irregular polygons are also given. In addition, properties of the mixedarea of a plane convex body and its polar dual are used to discuss the self-circumference of convexcurves.