  The Anomaly flow is shown to converge on toric fibrations with the Fu-Yau
ansatz, for both positive and negative values of the slope parameter $\alpha'$.
This implies both results of Fu and Yau on the existence of solutions for
Hull-Strominger systems, which they proved using different methods depending on
the sign of $\alpha'$. It is also the first case where the Anomaly flow can
even be shown to exist for all time. This is in itself remarkable from the
point of view of the theory of fully nonlinear partial differential equations,
as the elliptic terms in the flow are not concave.
