Deliberations on 11D superspace for the M-theory effective action

In relation to the superspace modifications of 11D supergeometry required t o describe the M-theory low-energy effective action, we present an analysis of infinitesimal supergravity fluctuations about the flat superspace limit . Our investigation confirms Howe's interpretation of our previous Bianchi identity analysis. However, the analysis also shows that should 11D supergr avity obey the rules of other off-shell supergravity theories, the complete M-theory corrections will necessarily excite our previously anticipated sp in-1/2 engineering dimension-1/2 spinor auxiliary multiplet superfield. The analysis of fluctuations yields more evidence that Hows's 1997 theorem is specious when applied to Poincare supergravity or 11D supergravity/M-theory . We end by commenting upon recent advances in this area. (C) 2001 Publishe d by Elsevier Science B.V.