The Largest Contained Quadrilateral and the Smallest Enclosing Parallelogram of a Convex Polygon
arXiv:1905.11203
Abstract
We present a linear-time algorithm for finding the quadrilateral of largest area contained in a convex polygon, and we show that it is closely related to an old algorithm for the smallest enclosing parallelogram of a convex polygon.
7 pages + 4 pages of appendices, 4 figures, plus a prototype implementation in Python. This version is substantially extended, and the algorithms are given in pseudocode in the appendices. (Version 1 was only about the largest contained quadrilateral.)