Unifying R-symmetry in M-theory

In this contribution we address the following question: Is there a group with a fermionic presentation which unifies all the physical gravitini and dilatini of the maximal supergravity theories in D=10 and D=11 (without introducing new degrees of freedom)? The affirmative answer relies on a new mathematical object derived from the theory of Kac--Moody algebras, notably E10. It can also be shown that in this way not only the spectrum but also dynamical aspects of all supergravity theories can be treated uniformly.