Editing Supergravity (section)

==Relation to superstrings==
The term "low energy limits" labels some 10-dimensional supergravity theories.  These arise as the massless, [[tree (graph theory)|tree]]-level approximation of string theories. True [[effective field theories]] of string theories, rather than truncations, are rarely available. Due to string dualities, the conjectured 11-dimensional M-theory is required to have 11-dimensional supergravity as a "low energy limit". However, this doesn't necessarily mean that string theory/M-theory is the only possible [[UV completion]] of supergravity;{{Citation needed|date=March 2007}} supergravity research is useful independent of those relations.