On melancholic magic squares
Dietrich Trenkler, G�tz Trenkler · Discussiones Mathematicae Probability and Statistics · 2013
Starting with Drer's magic square which appears in the well-known copper plate engraving Melencolia we consider the class of melancholic magic squares. Each member of this class exhibits the same 86 patterns of Drer's magic square and is magic again. Special attention is paid to the eigenstructure of melancholic magic squares, their group inverse and their Moore-Penrose inverse. It is seen how the patterns of the original Drer square to a large extent are passed down also to the inverses of the melancholic magic squares.