XY-pic is a software package that provides an easy way to specify the content and layout of mathematical diagrams and technical graphics of kinds which are common in various fields of mathematics, computer science, and other fields.
Developed initially by Kristoffer Rose (IBM Research) and extended in collaboration with Ross Moore (Mathematics, Macquarie), XY-pic integrates seamlessly with the software usually used to produce mathematical manuscripts, so has great applicability in the production of journals and research articles, both for paper printing and online delivery.
The Xy-pic package started out as a means for Rose to present his M.Sc. thesis at BRICS (Aarhus, Denmark) in the early 1990s, but was quickly seen to be applicable to a wide range of mathematical graphics, in particular for the “commutative diagrams” of Abstract Algebra and Category Theory.
Collaboration between Moore and Rose led to significant extensions, both in the technical output formats produced, as well as simplified support for different kinds of graphic elements needed in various branches of mathematics.
The Xy-pic package is used by many authors in preparing their manuscripts for publication and projection slides for lectures.
It integrates perfectly with the LaTeX software that is most commonly used. Almost every paper that appears in Category Theory nowadays uses Xy-pic for its diagrams, either directly or implicitly using other software built on top of an Xy-pic base. As software changes for the online delivery of mathematical content, Xy-pic receives appropriate updates to remain as useful now as it was 20 years ago.