This option computes the maps from natural free bundles which generates the Beilinson bundles U^a to natural free bundles which contains the Beilinson bundles U^a as subbundles. In other words, this option provides a map between free modules \wedge^{a+1}W\otimes S(-1)\to \wedge^{a}W\otimes S which factors through U^a where W=S_1. In particular, it represents a natural embedding of U^a into the corresponding free bundle.
The object MapsBetweenFreeBundles is a symbol.