The Elway Theorem was a proposal for a new method of transportation that was first advanced sometime before the mid 23rd century. The theory concerned Folded-space transport and was explored by several approaches before ultimately being proved invalid and abandoned.
In 2366 Wesley Crusher, having recently studied the theorem, suggested an alternate version of it might explain the unknown transporter technology being used by the Ansata separatist group on Rutia IV. (TNG: "The High Ground")