2008/11/04 by Boya, Luis J.
#FOS: Physical sciences #Mathematical Physics (math-ph)
paper · doi:10.48550/arxiv.0811.0554
We adress the problem of the reasons for the existence of 12 symmetric spaces with the exceptional Lie groups. The 1+2 cases for G2 and F4 respectively are easily explained from the octonionic nature of these groups. The 4+3+2 cases on the E6,7,8 series require the magic square of Freudenthal and, for the split case, an appeal to the supergravity chain in 5, 4 and 3 spacetime dimensions.