It has been known that D=5 simple supergravity resembles D=11 supergravity in
many respects. We present their further resemblances in (1) the duality groups
upon dimensional reduction, and (2) the worldsheet structure of the solitonic
string of the D=5 supergravity. We show that the D=3, G_{2(+2)}/SO(4) (bosonic)
nonlinear sigma model is obtained by using Freudenthal's construction in
parallel to the derivation of the D=3, E_{8(+8)}/SO(16) sigma model from D=11
supergravity. The zero modes of the string solution with unbroken (4,0)
supersymmetry consist of three (non-chiral) scalars, four Majorana-Weyl spinors
of the same chirality and one chiral scalar, which suggests a duality to a
certain six-dimensional chiral string theory. The worldsheet gravitational
anomaly indicates a quantum correction to the Bianchi identity for the dualized
two-form gauge field in the bulk just like the M5-brane case.Comment: 12 pages, references adde
