A deceased man (Thomas Trobaugh) was considered a coauthor of a 1990 math paper after he appeared in a dream to the other author to explain some of the key ideas.
gwern.net, Tiny Fox Lab

A deceased man (Thomas Trobaugh) was considered a coauthor of a 1990 math paper after he appeared in a dream to the other author to explain some of the key ideas. – Tiny Fox Lab Facts

Preview photo credit: gwern.net
Source: gwern.net/docs/m…