A reverse isoperimetric inequality for embedded starshaped plane curves

摘要

In this note, we present a reverse isoperimetric inequality for embedded starshaped closed plane curves, which states that if K is a starshaped domain with perimeter p(K) and area a(K), then one gets where denotes the oriented area of the domain enclosed by (defined in Section 2), and equality holds if and only if K is a disc.