From E₈to F via T

We argue that T-duality and F-theory appear automatically in the E₈``gauge'' bundle perspective of M-theory. The 11-dimensional supergravity four-form determines an E₈bundle over the 11-dimensional bulk. If we compactify on a two-torus, this data specifies an LLE₈bundle over the remaining 9-dimensions where LG is a centrally-extended loopgroup of G. If one of the circles of the torus is smaller than (α')^1/2then it is also smaller than a nontrivial circle S in the LLE₈fiber and so a dimensional reduction on the total space of the LLE₈bundle is not valid. We conjecture that S is the circle on which the T-dual type IIB supergravity is compactified, with the aforementioned torus playing the role of the F-theory torus. As tests we reproduce the known T-dualities between NS5-branes and KK-monopoles, as well as D6 and D7-branes where we find the desired F-theory monodromy. Using Hull's proposal for massive IIA, this realization of T-duality allows us to confirm that the Romans mass is the central extension of our LE₈. In addition this construction immediately reproduces the conjectured formula for global topology change from T-duality with H-flux.