Comments on the relation of M-theory and supergravity

M-theory was synthesized in 1995 due to observations regarding an intricate web-of-dualities that relate the five superstring theories, and recognition that D=11 supergravity is both nonperturbatively dual to type-IIA superstring and the low-energy limit of an 11-dimensional theory. Mutual development of M-theory and supergravity ensued. During the past three years, related but independent field theory calculations suggest that N=8 d=4 supergravity scattering amplitudes may be ultraviolet finite. Since supergravity theories represent the low-energy effective actions of string theories and describe the interaction of massless fields in the string theory spectrum, it is noteworthy that it was suggested recently that N=8 supergravity, in the event stringy states are discarded, is inconsistent and thus in the Swampland. This thesis proposes a different interpretation based on results that integrate BPS-soliton states and strengthen the symbiotic relationship between N=8 supergravity and M-theory, which would lead to mutual development