arXiv subjects
Publications and source records attributed to Annalisa Crannell.
When is it possible to project two sets of labeled points lying in a pair of projective planes to the same image on a projective line? We give a complete answer to this question and describe the loci of the projection centers that enable a common image. In particular, we find that there exists a solution to this problem if and only if these two sets are themselves images of a common pointset in projective space.
On the 500th anniversary of Albrecht Dürer's copperplate engraving Melencolia I, we invite readers to join in a time-honored "party game" that has attracted art historians and scientists for many years: guessing the nature and meaning of the composition's enigmatic stone polyhedron. Our main purpose is to demonstrate the usefulness of the cross ratio in the analysis of works in perspective. We show how the cross ratio works as a projectively invariant "shape parameter" of the polyhedron, and how it can be used in analyzing various theories of this figure.